Description

Elastic gear coupling between two shafts.

#include <ChShaftsLoads.h>

Inheritance diagram for chrono::ChShaftsElasticGear:

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Collaboration diagram for chrono::ChShaftsElasticGear:

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Public Member Functions
	ChShaftsElasticGear (std::shared_ptr< ChShaft > shaft1, std::shared_ptr< ChShaft > shaft2, const double stiffness, const double damping, const double Ra, const double ratio=-1)

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

void	SetTeethStiffness (const double stiffness)
	Set teeth stiffness, at contact point, in tangent direction to the two primitives.

double	GetTeethStiffness () const

void	SetTeethDamping (const double damping)
	Set teeth damping, at contact point, in tangent direction to the two primitives.

double	GetTeethDamping () const

void	SetRestPhase (const double phase)
	Set the phase shaft1-tau*shaft2 for zero compression of the spring (default = 0).

double	GetRestPhase () const

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

void	SetTransmissionRatioFromRadii (double Ra, double Rb, bool internal=false)
	Set the transmission ratio t, as in w2=t*w1, using the two primitive radii Ra and Rb. More...

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

double	GetGearRadius1 () const
	Get the primitive radius of the gear wheel of shaft1.

double	GetGearRadius2 () const
	Get the primitive radius of the gear wheel of shaft2.

double	GetContactForce () const
	Get the last computed contact force, for diagnostics. More...

Public Member Functions inherited from chrono::ChLoadCustomMultiple
	ChLoadCustomMultiple (std::vector< std::shared_ptr< ChLoadable >> &loadable_objects)

	ChLoadCustomMultiple (std::shared_ptr< ChLoadable > loadableA, std::shared_ptr< ChLoadable > loadableB)

	ChLoadCustomMultiple (std::shared_ptr< ChLoadable > loadableA, std::shared_ptr< ChLoadable > loadableB, std::shared_ptr< ChLoadable > loadableC)

virtual int	LoadGetNumCoordsPosLevel () override
	Gets the number of DOFs affected by this load (position part).

virtual int	LoadGetNumCoordsVelLevel () override
	Gets the number of DOFs affected by this load (speed part).

virtual void	LoadGetStateBlock_x (ChState &mD) override
	Gets all the current DOFs packed in a single vector (position part).

virtual void	LoadGetStateBlock_w (ChStateDelta &mD) override
	Gets all the current DOFs packed in a single vector (speed part).

virtual void	LoadStateIncrement (const ChState &x, const ChStateDelta &dw, ChState &x_new) override
	Increment a packed state (e.g., as obtained by LoadGetStateBlock_x()) by a given packed state-delta. More...

virtual int	LoadGetNumFieldCoords () override
	Number of coordinates in the interpolated field. More...

virtual void	ComputeJacobian (ChState state_x, ChStateDelta state_w) override
	Compute Jacobian matrices K=-dQ/dx, R=-dQ/dv, and M=-dQ/da. More...

virtual void	LoadIntLoadResidual_F (ChVectorDynamic<> &R, double c) override
	Add the internal loads Q (pasted at global offsets) into a global vector R, multiplied by a scaling factor c. More...

virtual void	LoadIntLoadResidual_Mv (ChVectorDynamic<> &R, const ChVectorDynamic<> &w, double c) override
	Increment a vector R with the matrix-vector product M*w, scaled by the factor c. More...

virtual void	LoadIntLoadLumpedMass_Md (ChVectorDynamic<> &Md, double &err, const double c) override
	Add the lumped mass to an Md vector, representing a mass diagonal matrix. More...

virtual void	CreateJacobianMatrices () override
	Create the Jacobian loads if needed and set the ChVariables referenced by the sparse KRM block.

virtual ChVectorDynamic &	GetQ ()
	Access the generalized load vector Q.

Public Member Functions inherited from chrono::ChLoadBase
ChLoadJacobians *	GetJacobians ()
	Access the Jacobians (if any, i.e. if this is a stiff load).

virtual void	Update (double time)
	Update, called at least at each time step. More...

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...

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 void	ArchiveOut (ChArchiveOut &archive_out)
	Method to allow serialization of transient data to archives.

virtual void	ArchiveIn (ChArchiveIn &archive_in)
	Method to allow de-serialization of transient data from archives.

virtual std::string &	ArchiveContainerName ()

Protected Member Functions
virtual bool	IsStiff () override
	Report if this is load is stiff. More...

virtual void	ComputeQ (ChState state_x, ChStateDelta state_w) override
	Compute Q, the generalized load. More...

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

Protected Attributes
double	m_stiffness

double	m_damping

double	m_rest_phase

double	m_Ra

double	m_ratio

double	m_contact_force

Protected Attributes inherited from chrono::ChLoadBase
ChLoadJacobians *	m_jacobians

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

Additional Inherited Members
Public Attributes inherited from chrono::ChLoadCustomMultiple
std::vector< std::shared_ptr< ChLoadable > >	loadables

ChVectorDynamic	load_Q

Constructor & Destructor Documentation

◆ ChShaftsElasticGear()

chrono::ChShaftsElasticGear::ChShaftsElasticGear	(	std::shared_ptr< ChShaft >	shaft1,
		std::shared_ptr< ChShaft >	shaft2,
		const double	stiffness,
		const double	damping,
		const double	Ra,
		const double	ratio = `-1`
	)

Parameters

shaft1	first shaft
shaft2	second shaft
stiffness	normal stiffness at teeth contact, tangent direction to primitive
damping	normal damping at teeth contact, tangent direction to primitive
Ra	primitive radius of the gear on shaft A (the radius of B is not needed)
ratio	transmission ratio (negative for outer gear, positive for inner gears)

Member Function Documentation

◆ ComputeQ()

void chrono::ChShaftsElasticGear::ComputeQ	(	ChState *	state_x,
		ChStateDelta *	state_w
	)

overrideprotectedvirtual

Compute Q, the generalized load.

Called automatically at each Update().

Parameters

state_x	state position to evaluate Q
state_w	state speed to evaluate Q

Implements chrono::ChLoadBase.

◆ GetContactForce()

double chrono::ChShaftsElasticGear::GetContactForce ( ) const

inline

Get the last computed contact force, for diagnostics.

The force is assumed tangent to the primitives of the gear wheels, it can be positive or negative depending on clock/counterclock effect.

◆ IsStiff()

virtual bool chrono::ChShaftsElasticGear::IsStiff ( )

inlineoverrideprotectedvirtual

Report if this is load is stiff.

If so, InjectKRMMatrices will provide the Jacobians of the load.

Implements chrono::ChLoadBase.

◆ SetTransmissionRatioAndRadiusA()

void chrono::ChShaftsElasticGear::SetTransmissionRatioAndRadiusA	(	double	ratio,
		double	Ra
	)

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. Differently from the ideal ChShaftsGear constraint, this model includes elasticity, so at least the radius of one of the two gear wheels is needed, namely Ra.

◆ SetTransmissionRatioFromRadii()

void chrono::ChShaftsElasticGear::SetTransmissionRatioFromRadii	(	double	Ra,
		double	Rb,
		bool	internal = `false`
	)

Set the transmission ratio t, as in w2=t*w1, using the two primitive radii Ra and Rb.

It will be computed as t=Ra/Rb by default, otherwise t=-Ra/Rb if the bigger wheel has inner teeth.

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

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

Description

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members