Description

Base class for a tire system.

A tire subsystem is a force element. It is passed position and velocity information of the wheel body and it produces ground reaction forces and moments to be applied to the wheel body.

#include <ChTire.h>

Inheritance diagram for chrono::vehicle::ChTire:

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Collaboration diagram for chrono::vehicle::ChTire:

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Public Types
enum	CollisionType { SINGLE_POINT, FOUR_POINTS, ENVELOPE }

Public Member Functions
	ChTire (const std::string &name)

void	SetStepsize (double val)
	Set the value of the integration step size for the underlying dynamics (if applicable). More...

double	GetStepsize () const
	Get the current value of the integration step size.

void	SetCollisionType (CollisionType collision_type)
	Set the collision type for tire-terrain interaction. More...

virtual double	GetRadius () const =0
	Get the tire radius.

virtual double	GetMass () const =0
	Get the tire mass. More...

virtual double	ReportMass () const
	Report the tire mass. More...

virtual ChVector	GetInertia () const =0
	Get the tire moments of inertia. More...

virtual TerrainForce	ReportTireForce (ChTerrain *terrain) const =0
	Report the tire force and moment. More...

double	GetSlipAngle () const
	Return the tire slip angle calculated based on the current state of the associated wheel body. More...

double	GetLongitudinalSlip () const
	Return the tire longitudinal slip calculated based on the current state of the associated wheel body. More...

double	GetCamberAngle () const
	Return the tire camber angle calculated based on the current state of the associated wheel body. More...

virtual double	GetDeflection () const
	Report the tire deflection.

virtual void	Initialize (std::shared_ptr< ChWheel > wheel)
	Initialize this tire subsystem by associating it to an existing wheel subsystem. More...

virtual void	Synchronize (double time, const ChTerrain &terrain)
	Update the state of this tire system at the current time. More...

virtual void	Advance (double step)
	Advance the state of this tire by the specified time step.

Public Member Functions inherited from chrono::vehicle::ChPart
	ChPart (const std::string &name)
	Construct a vehicle subsystem with the specified name. More...

const std::string &	GetName () const
	Get the name identifier for this subsystem.

void	SetName (const std::string &name)
	Set the name identifier for this subsystem.

virtual std::string	GetTemplateName () const =0
	Get the name of the vehicle subsystem template.

void	SetVisualizationType (VisualizationType vis)
	Set the visualization mode for this subsystem.

virtual void	AddVisualizationAssets (VisualizationType vis)
	Add visualization assets to this subsystem, for the specified visualization mode.

virtual void	RemoveVisualizationAssets ()
	Remove all visualization assets from this subsystem.

void	SetContactFrictionCoefficient (float friction_coefficient)
	Set coefficient of friction. More...

void	SetContactRestitutionCoefficient (float restitution_coefficient)
	Set coefficient of restitution. More...

void	SetContactMaterialProperties (float young_modulus, float poisson_ratio)
	Set contact material properties. More...

void	SetContactMaterialCoefficients (float kn, float gn, float kt, float gt)
	Set contact material coefficients. More...

float	GetCoefficientFriction () const
	Get coefficient of friction for contact material.

float	GetCoefficientRestitution () const
	Get coefficient of restitution for contact material.

float	GetYoungModulus () const
	Get Young's modulus of elasticity for contact material.

float	GetPoissonRatio () const
	Get Poisson ratio for contact material.

float	GetKn () const
	Get normal stiffness coefficient for contact material.

float	GetKt () const
	Get tangential stiffness coefficient for contact material.

float	GetGn () const
	Get normal viscous damping coefficient for contact material.

float	GetGt () const
	Get tangential viscous damping coefficient for contact material.

virtual void	SetOutput (bool state)
	Enable/disable output for this subsystem.

bool	OutputEnabled () const
	Return the output state for this subsystem.

virtual void	ExportComponentList (rapidjson::Document &jsonDocument) const
	Export this subsystem's component list to the specified JSON object. More...

virtual void	Output (ChVehicleOutput &database) const
	Output data for this subsystem's component list to the specified database.

Static Public Member Functions
static ChVector	EstimateInertia (double tire_width, double aspect_ratio, double rim_diameter, double tire_mass, double t_factor=2)
	Utility function for estimating the tire moments of inertia. More...

Static Public Member Functions inherited from chrono::vehicle::ChPart
static ChMatrix33	TransformInertiaMatrix (const ChVector<> &moments, const ChVector<> &products, const ChMatrix33<> &vehicle_rot, const ChMatrix33<> &body_rot)
	Utility function for transforming inertia tensors between centroidal frames. More...

Protected Member Functions
void	CalculateKinematics (double time, const WheelState &wheel_state, const ChTerrain &terrain)
	Calculate kinematics quantities based on the given state of the associated wheel body. More...

double	GetOffset () const
	Get offset from spindle center. More...

virtual TerrainForce	GetTireForce () const =0
	Get the tire force and moment. More...

std::shared_ptr< ChTriangleMeshShape >	AddVisualizationMesh (const std::string &mesh_file_left, const std::string &mesh_file_right)
	Add mesh visualization to the body associated with this tire (a wheel spindle body). More...

void	RemoveVisualizationMesh (std::shared_ptr< ChTriangleMeshShape > trimesh_shape)
	Remove the specified mesh shape from the visualization assets of the body associated with this tire (a wheel spindle body).

Protected Member Functions inherited from chrono::vehicle::ChPart
virtual void	Create (const rapidjson::Document &d)
	Create a vehicle subsystem from JSON data. More...

Static Protected Member Functions
static bool	DiscTerrainCollision (const ChTerrain &terrain, const ChVector<> &disc_center, const ChVector<> &disc_normal, double disc_radius, ChCoordsys<> &contact, double &depth)
	Perform disc-terrain collision detection. More...

static bool	DiscTerrainCollision4pt (const ChTerrain &terrain, const ChVector<> &disc_center, const ChVector<> &disc_normal, double disc_radius, double width, ChCoordsys<> &contact, double &depth, double &camber_angle)
	Perform disc-terrain collision detection considering the curvature of the road surface. More...

static bool	DiscTerrainCollisionEnvelope (const ChTerrain &terrain, const ChVector<> &disc_center, const ChVector<> &disc_normal, double disc_radius, const ChFunction_Recorder &areaDep, ChCoordsys<> &contact, double &depth)
	Collsion algorithm based on a paper of J. More...

static void	ConstructAreaDepthTable (double disc_radius, ChFunction_Recorder &areaDep)
	Utility function to construct a loopkup table for penetration depth as function of intersection area, for a given tire radius. More...

Static Protected Member Functions inherited from chrono::vehicle::ChPart
static void	ExportBodyList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChBody >> bodies)
	Export the list of bodies to the specified JSON document.

static void	ExportShaftList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChShaft >> shafts)
	Export the list of shafts to the specified JSON document.

static void	ExportJointList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChLink >> joints)
	Export the list of joints to the specified JSON document.

static void	ExportCouplesList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChShaftsCouple >> couples)
	Export the list of shaft couples to the specified JSON document.

static void	ExportMarkerList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChMarker >> markers)
	Export the list of markers to the specified JSON document.

static void	ExportLinSpringList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChLinkTSDA >> springs)
	Export the list of translational springs to the specified JSON document.

static void	ExportRotSpringList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChLinkRotSpringCB >> springs)
	Export the list of rotational springs to the specified JSON document.

static void	ExportBodyLoadList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChLoadBodyBody >> loads)
	Export the list of body-body loads to the specified JSON document.

Protected Attributes
std::shared_ptr< ChWheel >	m_wheel
	associated wheel subsystem

double	m_stepsize
	tire integration step size (if applicable)

CollisionType	m_collision_type
	method used for tire-terrain collision

Protected Attributes inherited from chrono::vehicle::ChPart
std::string	m_name
	subsystem name

bool	m_output
	specifies whether or not output is generated for this subsystem

float	m_friction
	contact coefficient of friction

float	m_restitution
	contact coefficient of restitution

float	m_young_modulus
	contact material Young modulus

float	m_poisson_ratio
	contact material Poisson ratio

float	m_kn
	normal contact stiffness

float	m_gn
	normal contact damping

float	m_kt
	tangential contact stiffness

float	m_gt
	tangential contact damping

Friends
class	ChWheel

Constructor & Destructor Documentation

◆ ChTire()

chrono::vehicle::ChTire::ChTire ( const std::string & name )

Parameters

[in] name name of this tire system

Member Function Documentation

◆ AddVisualizationMesh()

std::shared_ptr< ChTriangleMeshShape > chrono::vehicle::ChTire::AddVisualizationMesh	(	const std::string &	mesh_file_left,
		const std::string &	mesh_file_right
	)

protected

Add mesh visualization to the body associated with this tire (a wheel spindle body).

The two meshes are assumed to be specified with respect to a frame with origin at the center of the tire and Y axis pointing towards the outside. This function uses one of the two provided OBJ files, depending on the side on which the tire is mounted. The name of the output mesh shape is set to be the stem of the input filename.

◆ CalculateKinematics()

void chrono::vehicle::ChTire::CalculateKinematics	(	double	time,
		const WheelState &	wheel_state,
		const ChTerrain &	terrain
	)

protected

Calculate kinematics quantities based on the given state of the associated wheel body.

Parameters

[in]	time	current time
[in]	wheel_state	current state of associated wheel body
[in]	terrain	reference to the terrain system

◆ ConstructAreaDepthTable()

void chrono::vehicle::ChTire::ConstructAreaDepthTable	(	double	disc_radius,
		ChFunction_Recorder &	areaDep
	)

staticprotected

Utility function to construct a loopkup table for penetration depth as function of intersection area, for a given tire radius.

The return map can be used in DiscTerrainCollisionEnvelope.

◆ DiscTerrainCollision()

bool chrono::vehicle::ChTire::DiscTerrainCollision	(	const ChTerrain &	terrain,
		const ChVector<> &	disc_center,
		const ChVector<> &	disc_normal,
		double	disc_radius,
		ChCoordsys<> &	contact,
		double &	depth
	)

staticprotected

Perform disc-terrain collision detection.

This utility function checks for contact between a disc of specified radius with given position and orientation (specified as the location of its center and a unit vector normal to the disc plane) and the terrain system associated with this tire. It returns true if the disc contacts the terrain and false otherwise. If contact occurs, it returns a coordinate system with the Z axis along the contact normal and the X axis along the "rolling" direction, as well as a positive penetration depth (i.e. the height below the terrain of the lowest point on the disc).

Parameters

[in]	terrain	reference to terrain system
[in]	disc_center	global location of the disc center
[in]	disc_normal	disc normal, expressed in the global frame
[in]	disc_radius	disc radius
[out]	contact	contact coordinate system (relative to the global frame)
[out]	depth	penetration depth (positive if contact occurred)

◆ DiscTerrainCollision4pt()

bool chrono::vehicle::ChTire::DiscTerrainCollision4pt	(	const ChTerrain &	terrain,
		const ChVector<> &	disc_center,
		const ChVector<> &	disc_normal,
		double	disc_radius,
		double	width,
		ChCoordsys<> &	contact,
		double &	depth,
		double &	camber_angle
	)

staticprotected

Perform disc-terrain collision detection considering the curvature of the road surface.

The surface normal is calculated based on 4 different height values below the wheel center. The effective height is calculated as average value of the four height values. This utility function checks for contact between a disc of specified radius with given position and orientation (specified as the location of its center and a unit vector normal to the disc plane) and the terrain system associated with this tire. It returns true if the disc contacts the terrain and false otherwise. If contact occurs, it returns a coordinate system with the Z axis along the contact normal and the X axis along the "rolling" direction, as well as a positive penetration depth (i.e. the height below the terrain of the lowest point on the disc).

Parameters

[in]	terrain	reference to terrain system
[in]	disc_center	global location of the disc center
[in]	disc_normal	disc normal, expressed in the global frame
[in]	disc_radius	disc radius
[in]	width	tire width
[out]	contact	contact coordinate system (relative to the global frame)
[out]	depth	penetration depth (positive if contact occurred)
[out]	camber_angle	tire camber angle

◆ DiscTerrainCollisionEnvelope()

bool chrono::vehicle::ChTire::DiscTerrainCollisionEnvelope	(	const ChTerrain &	terrain,
		const ChVector<> &	disc_center,
		const ChVector<> &	disc_normal,
		double	disc_radius,
		const ChFunction_Recorder &	areaDep,
		ChCoordsys<> &	contact,
		double &	depth
	)

staticprotected

Collsion algorithm based on a paper of J.

Shane Sui and John A. Hirshey II: "A New Analytical Tire Model for Vehicle Dynamic Analysis" presented at 2001 MSC User Meeting

Parameters

[in]	terrain	reference to terrain system
[in]	disc_center	global location of the disc center
[in]	disc_normal	disc normal, expressed in the global frame
[in]	disc_radius	disc radius
[in]	areaDep	lookup table to calculate depth from intersection area
[out]	contact	contact coordinate system (relative to the global frame)
[out]	depth	penetration depth (positive if contact occurred)

◆ EstimateInertia()

ChVector chrono::vehicle::ChTire::EstimateInertia	(	double	tire_width,
		double	aspect_ratio,
		double	rim_diameter,
		double	tire_mass,
		double	t_factor = `2`
	)

static

Utility function for estimating the tire moments of inertia.

The tire is assumed to be specified with the common scheme (e.g. 215/65R15) and the mass of the tire (excluding the wheel) provided.

Parameters

tire_width	tire width [mm]
aspect_ratio	aspect ratio: height to width [percentage]
rim_diameter	rim diameter [in]
tire_mass	mass of the tire [kg]
t_factor	tread to sidewall thickness factor

◆ GetCamberAngle()

double chrono::vehicle::ChTire::GetCamberAngle ( ) const

inline

Return the tire camber angle calculated based on the current state of the associated wheel body.

The return value is in radians. (positive sign = upper side tipping to the left, negative sign = upper side tipping to the right)

◆ GetInertia()

virtual ChVector chrono::vehicle::ChTire::GetInertia ( ) const

pure virtual

Get the tire moments of inertia.

Note that these should not include the inertia of the wheel (rim).

◆ GetLongitudinalSlip()

double chrono::vehicle::ChTire::GetLongitudinalSlip ( ) const

inline

Return the tire longitudinal slip calculated based on the current state of the associated wheel body.

(positive sign = driving, negative sign = breaking)

◆ GetMass()

virtual double chrono::vehicle::ChTire::GetMass ( ) const

pure virtual

Get the tire mass.

Note that this should not include the mass of the wheel (rim).

◆ GetOffset()

double chrono::vehicle::ChTire::GetOffset ( ) const

inlineprotected

Get offset from spindle center.

This queries the associated wheel, so it must be called only after the wheel was initialized.

◆ GetSlipAngle()

double chrono::vehicle::ChTire::GetSlipAngle ( ) const

inline

Return the tire slip angle calculated based on the current state of the associated wheel body.

The return value is in radians. (positive sign = left turn, negative sign = right turn)

◆ GetTireForce()

virtual TerrainForce chrono::vehicle::ChTire::GetTireForce ( ) const

protectedpure virtual

Get the tire force and moment.

This represents the output from this tire system that is passed to the vehicle system. Typically, the vehicle subsystem will pass the tire force to the appropriate suspension subsystem which applies it as an external force on the wheel body. NOTE: tire models that rely on underlying Chrono functionality (e.g., the Chrono contact system or Chrono constraints) must always return zero forces and moments, else tire forces are double counted.

◆ Initialize()

void chrono::vehicle::ChTire::Initialize ( std::shared_ptr< ChWheel > wheel )

virtual

Initialize this tire subsystem by associating it to an existing wheel subsystem.

The tire mass and inertia are used to increment those of the associated suspension spindle body.

◆ ReportMass()

double chrono::vehicle::ChTire::ReportMass ( ) const

virtual

Report the tire mass.

Certain tire models (e.g. those based on FEA) must return 0 in GetMass() so that the tire mass is not double counted in the underlying mechanical system. For reporting purposes, use this function instead.

Reimplemented in chrono::vehicle::ChDeformableTire.

◆ ReportTireForce()

virtual TerrainForce chrono::vehicle::ChTire::ReportTireForce ( ChTerrain * terrain ) const

pure virtual

Report the tire force and moment.

This function can be used for reporting purposes or else to calculate tire forces in a co-simulation framework.

Implemented in chrono::vehicle::ChDeformableTire, chrono::vehicle::ChPacejkaTire, chrono::vehicle::ChTMeasyTire, chrono::vehicle::ChPac02Tire, chrono::vehicle::ChRigidTire, chrono::vehicle::ChPac89Tire, chrono::vehicle::ChFialaTire, and chrono::vehicle::ChLugreTire.

◆ SetCollisionType()

void chrono::vehicle::ChTire::SetCollisionType ( CollisionType collision_type )

inline

Set the collision type for tire-terrain interaction.

Default: SINGLE_POINT

◆ SetStepsize()

void chrono::vehicle::ChTire::SetStepsize ( double val )

inline

Set the value of the integration step size for the underlying dynamics (if applicable).

Default value: 1ms.

◆ Synchronize()

virtual void chrono::vehicle::ChTire::Synchronize	(	double	time,
		const ChTerrain &	terrain
	)

inlinevirtual

Update the state of this tire system at the current time.

Parameters

[in]	time	current time
[in]	terrain	reference to the terrain system

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

/builds/uwsbel/chrono/src/chrono_vehicle/wheeled_vehicle/ChTire.h
/builds/uwsbel/chrono/src/chrono_vehicle/wheeled_vehicle/ChTire.cpp

Description

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Friends

Constructor & Destructor Documentation

◆ ChTire()

Member Function Documentation

◆ AddVisualizationMesh()

◆ CalculateKinematics()

◆ ConstructAreaDepthTable()

◆ DiscTerrainCollision()

◆ DiscTerrainCollision4pt()

◆ DiscTerrainCollisionEnvelope()

◆ EstimateInertia()

◆ GetCamberAngle()

◆ GetInertia()

◆ GetLongitudinalSlip()

◆ GetMass()

◆ GetOffset()

◆ GetSlipAngle()

◆ GetTireForce()

◆ Initialize()

◆ ReportMass()

◆ ReportTireForce()

◆ SetCollisionType()

◆ SetStepsize()

◆ Synchronize()