Description

Class for defining a 'transmission ratio' (a 1D gear) between two one-degree-of-freedom parts.

Note that this really simple constraint does not provide a way to transmit a reaction force to the truss, if this is needed, just use the ChShaftsPlanetary with a fixed carrier shaft, or the ChShaftGearbox.

#include <ChShaftsGear.h>

Inheritance diagram for chrono::ChShaftsGear:

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Collaboration diagram for chrono::ChShaftsGear:

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Public Member Functions
	ChShaftsGear (const ChShaftsGear &other)

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

virtual unsigned int	GetNumConstraintsBilateral () override
	Number of scalar constraints.

void	SetTransmissionRatio (double t)
	Set the transmission ratio t, as in w2=tw1, or t=w2/w1 , or tw1 - w2 = 0. More...

double	GetTransmissionRatio () const
	Get the transmission ratio t, as in w2=t*w1, or t=w2/w1.

void	AvoidPhaseDrift (bool avoid)
	Enable phase drift avoidance (default: true). More...

double	GetReaction1 () const override
	Get the reaction torque exchanged between the two shafts, considered as applied to the 1st axis.

double	GetReaction2 () const override
	Get the reaction torque exchanged between the two shafts, considered as applied to the 2nd axis.

double	GetConstraintViolation () const
	Return current constraint violation.

bool	Initialize (std::shared_ptr< ChShaft > shaft_1, std::shared_ptr< ChShaft > shaft_2) override
	Initialize this shafts gear, given two shafts to join. More...

void	SetCompliant (bool mset, double mstiffness=1e4, double mdamping=1.0)
	Switch to compliant gear teeth contact model. More...

void	SetRigid ()
	Switch off compliant gear teeth contact model.

bool	IsCompliant () const
	Is the compliant gear teeth contact model used?

void	SetTorsionalStiffness (double mstiffness)
	Set the torsional stiffness [Nm/rad] for compliant gear model, for example because of compliance in teeth. More...

double	GetTorsionalStiffness () const
	Get the torsional stiffness [Nm/rad] for compliant gear model. More...

void	SetTeethStiffnessTangential (double mstiffness_tang, double radius_2)
	Set the stiffness for compliant gear model, starting from the stiffness [N/m] of teeth contact. More...

void	SetTorsionalDamping (double damping)
	Set the teeth damping [Nm/(rad/s)] for compliant gear model. More...

double	GetTorsionalDamping () const
	Get the teeth damping [Nm/(rad/s)] for compliant gear model. More...

double	GetContactForceTangential (double radius_2)
	Equivalent contact force between gear teeth, as for beta=0 and alpha=0. 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::ChShaftsCouple
	ChShaftsCouple (const ChShaftsCouple &other)

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

ChShaft *	GetShaft1 () const
	Get the first (input) shaft.

ChShaft *	GetShaft2 () const
	Get the second (output) shaft.

double	GetRelativePos () const
	Get the actual relative position (angle or displacement) in terms of phase of shaft 1 with respect to 2.

double	GetRelativePosDt () const
	Get the actual relative speed (angle or displacement) of shaft 1 with respect to 2.

double	GetRelativePosDt2 () const
	Get the actual relative acceleration (angle or displacement) of shaft 1 with respect to 2.

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...

virtual bool	IsActive () const
	Return true if the object is active and included in dynamics.

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 collision 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...

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 Lagrange 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 Lagrange 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, UpdateFlags update_flags)
	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	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	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.

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.

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 ChFrame	GetVisualModelFrame (unsigned int nclone=0) const
	Get the reference frame (expressed in and relative to the absolute frame) of the visual model. More...

virtual unsigned int	GetNumVisualModelClones () const
	Return the number of clones of the visual model associated with this object. More...

void	AddCamera (std::shared_ptr< ChCamera > camera)
	Attach a camera to this object. More...

std::vector< std::shared_ptr< ChCamera > >	GetCameras () const
	Get the set of cameras attached to this object.

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

virtual std::string &	ArchiveContainerName ()

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

Protected Attributes inherited from chrono::ChShaftsCouple
ChShaft *	shaft1
	first shaft

ChShaft *	shaft2
	second shaft

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

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 Lagrange 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

std::shared_ptr< ChVisualModelInstance >	vis_model_instance
	instantiated visualization model

std::vector< std::shared_ptr< ChCamera > >	cameras
	set of cameras

Member Function Documentation

◆ AvoidPhaseDrift()

void chrono::ChShaftsGear::AvoidPhaseDrift ( bool avoid )

inline

Enable phase drift avoidance (default: true).

If true, phasing is always tracked and the constraint is satisfied also at the position level. If false, microslipping can accumulate (as in friction wheels).

◆ GetContactForceTangential()

double chrono::ChShaftsGear::GetContactForceTangential ( double radius_2 )

Equivalent contact force between gear teeth, as for beta=0 and alpha=0.

Since this 1D model has no information about the radius of the gear, radius_2 (the primitive radius of the 2nd gear) must be provided.

◆ GetTorsionalDamping()

double chrono::ChShaftsGear::GetTorsionalDamping ( ) const

inline

Get the teeth damping [Nm/(rad/s)] for compliant gear model.

Assumed as torsional damping of the SECOND shaft, when first is fixed.

◆ GetTorsionalStiffness()

double chrono::ChShaftsGear::GetTorsionalStiffness ( ) const

inline

Get the torsional stiffness [Nm/rad] for compliant gear model.

Assumed as torsional stiffness of the SECOND shaft, when first is fixed.

◆ Initialize()

bool chrono::ChShaftsGear::Initialize	(	std::shared_ptr< ChShaft >	shaft_1,
		std::shared_ptr< ChShaft >	shaft_2
	)

overridevirtual

Initialize this shafts gear, given two shafts to join.

Both shafts must belong to the same ChSystem.

Parameters

shaft_1	first shaft to join
shaft_2	second shaft to join

Reimplemented from chrono::ChShaftsCouple.

◆ SetCompliant()

void chrono::ChShaftsGear::SetCompliant	(	bool	mset,
		double	mstiffness = `1e4`,
		double	mdamping = `1.0`
	)

Switch to compliant gear teeth contact model.

Automatically calls AvoidPhaseDrift(true), needed for compliant teeth.

◆ SetTeethStiffnessTangential()

void chrono::ChShaftsGear::SetTeethStiffnessTangential	(	double	mstiffness_tang,
		double	radius_2
	)

Set the stiffness for compliant gear model, starting from the stiffness [N/m] of teeth contact.

Equivalent stiffenss of teeth assumed in the tangential direction of contact. The gear torsional stiffness will be automatically computed as a consequence of tangential teeth stiffness and primitive radius of second gear. Automatically calls SetTeethCompliant and AvoidPhaseDrift(true), needed for compliant teeth.

◆ SetTorsionalDamping()

void chrono::ChShaftsGear::SetTorsionalDamping ( double damping )

Set the teeth damping [Nm/(rad/s)] for compliant gear model.

Automatically calls SetTeethCompliant and AvoidPhaseDrift(true), needed for compliant teeth. Assumed as torsional damping of the SECOND shaft, when first is fixed.

◆ SetTorsionalStiffness()

void chrono::ChShaftsGear::SetTorsionalStiffness ( double mstiffness )

Set the torsional stiffness [Nm/rad] for compliant gear model, for example because of compliance in teeth.

This is the torsional stiffness on the SECOND shaft, when the first is kept fixed. Automatically calls SetTeethCompliant and AvoidPhaseDrift(true), needed for compliant teeth.

◆ SetTransmissionRatio()

void chrono::ChShaftsGear::SetTransmissionRatio ( double t )

inline

Set the transmission ratio t, as in w2=t*w1, or t=w2/w1 , or t*w1 - w2 = 0.

For example, t=1 for a rigid joint; t=-0.5 for representing a couple of spur gears with teeth z1=20 & z2=40; t=0.1 for a gear with inner teeth (or epicycloidal reducer), etc.

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

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

Description

Public Member Functions

Additional Inherited Members

Member Function Documentation

◆ AvoidPhaseDrift()

◆ GetContactForceTangential()

◆ GetTorsionalDamping()

◆ GetTorsionalStiffness()

◆ Initialize()

◆ SetCompliant()

◆ SetTeethStiffnessTangential()

◆ SetTorsionalDamping()

◆ SetTorsionalStiffness()

◆ SetTransmissionRatio()