Description

Fiala based tire model.

#include <ChFialaTire.h>

Inheritance diagram for chrono::vehicle::ChFialaTire:
Collaboration diagram for chrono::vehicle::ChFialaTire:

Public Member Functions

 ChFialaTire (const std::string &name)
 
virtual std::string GetTemplateName () const override
 Get the name of the vehicle subsystem template.
 
virtual void Initialize (std::shared_ptr< ChBody > wheel, VehicleSide side) override
 Initialize this tire system. More...
 
virtual void AddVisualizationAssets (VisualizationType vis) override
 Add visualization assets for the rigid tire subsystem.
 
virtual void RemoveVisualizationAssets () override
 Remove visualization assets for the rigid tire subsystem.
 
virtual double GetRadius () const override
 Get the tire width. More...
 
virtual TerrainForce GetTireForce () const override
 Get the tire force and moment. More...
 
virtual TerrainForce ReportTireForce (ChTerrain *terrain) const override
 Report the tire force and moment.
 
virtual void Synchronize (double time, const WheelState &wheel_state, const ChTerrain &terrain, CollisionType collision_type=CollisionType::SINGLE_POINT) override
 Update the state of this tire system at the current time. More...
 
virtual void Advance (double step) override
 Advance the state of this tire by the specified time step.
 
double GetWidth () const
 Get the width of the tire.
 
virtual double GetVisualizationWidth () const
 Get visualization width.
 
double GetSlipAngle_internal () const
 Get the tire slip angle computed internally by the Fiala model (in radians). More...
 
double GetLongitudinalSlip_internal () const
 Get the tire longitudinal slip computed internally by the Fiala model. More...
 
double GetCamberAngle_internal ()
 Get the camber angle for the Fiala tire model (in radians). More...
 
void WritePlots (const std::string &plFileName, const std::string &plTireFormat)
 Generate basic tire plots. More...
 
- Public Member Functions inherited from chrono::vehicle::ChTire
 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.
 
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...
 
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.
 
- 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.
 
void SetVisualizationType (VisualizationType vis)
 Set the visualization mode for 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.
 

Protected Member Functions

virtual double GetNormalStiffnessForce (double depth) const =0
 Return the vertical tire stiffness contribution to the normal force.
 
virtual double GetNormalDampingForce (double depth, double velocity) const =0
 Return the vertical tire damping contribution to the normal force.
 
virtual void SetFialaParams ()=0
 Set the parameters in the Fiala model.
 
void FialaPatchForces (double &fx, double &fy, double &mz, double kappa, double alpha, double fz)
 Calculate Patch Forces.
 
- Protected Member Functions inherited from chrono::vehicle::ChPart
virtual void Create (const rapidjson::Document &d)
 Create a vehicle subsystem from JSON data. More...
 

Protected Attributes

double m_unloaded_radius
 Fiala tire model parameters.
 
double m_width
 
double m_rolling_resistance
 
double m_c_slip
 
double m_c_alpha
 
double m_u_min
 
double m_u_max
 
double m_relax_length_x
 
double m_relax_length_y
 
double m_mu
 Actual friction coefficient of the road.
 
double m_mu_0
 Local friction coefficient of the road for given parameters.
 
bool m_dynamic_mode
 Switch for dynamic mode (relaxation)
 
double m_time
 
double m_time_trans
 
- Protected Attributes inherited from chrono::vehicle::ChTire
VehicleSide m_side
 tire mounted on left/right side
 
std::shared_ptr< ChBodym_wheel
 associated wheel body
 
double m_stepsize
 tire integration step size (if applicable)
 
- 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
 

Additional Inherited Members

- Public Types inherited from chrono::vehicle::ChTire
enum  CollisionType { SINGLE_POINT, FOUR_POINTS, ENVELOPE }
 
- Static Public Member Functions inherited from chrono::vehicle::ChTire
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...
 
- Static Protected Member Functions inherited from chrono::vehicle::ChTire
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< ChLinkSpringCB >> 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.
 

Constructor & Destructor Documentation

chrono::vehicle::ChFialaTire::ChFialaTire ( const std::string &  name)
Parameters
[in]namename of this tire system

Member Function Documentation

double chrono::vehicle::ChFialaTire::GetCamberAngle_internal ( )

Get the camber angle for the Fiala tire model (in radians).

ChFialaTire does not calculate its own camber angle. This value is the same as that reported by ChTire::GetCamberAngle.

double chrono::vehicle::ChFialaTire::GetLongitudinalSlip_internal ( ) const

Get the tire longitudinal slip computed internally by the Fiala model.

The reported value will be different from that reported by ChTire::GetLongitudinalSlip because ChFialaTire uses the loaded tire radius for its calculation.

virtual double chrono::vehicle::ChFialaTire::GetRadius ( ) const
overridevirtual

Get the tire width.

For a Fiala tire, this is the unloaded tire radius.

Implements chrono::vehicle::ChTire.

double chrono::vehicle::ChFialaTire::GetSlipAngle_internal ( ) const

Get the tire slip angle computed internally by the Fiala model (in radians).

The reported value will be similar to that reported by ChTire::GetSlipAngle.

virtual TerrainForce chrono::vehicle::ChFialaTire::GetTireForce ( ) const
overridevirtual

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 one the wheel body.

Implements chrono::vehicle::ChTire.

void chrono::vehicle::ChFialaTire::Initialize ( std::shared_ptr< ChBody wheel,
VehicleSide  side 
)
overridevirtual

Initialize this tire system.

Parameters
[in]wheelassociated wheel body
[in]sideleft/right vehicle side

Reimplemented from chrono::vehicle::ChTire.

void chrono::vehicle::ChFialaTire::Synchronize ( double  time,
const WheelState wheel_state,
const ChTerrain terrain,
CollisionType  collision_type = CollisionType::SINGLE_POINT 
)
overridevirtual

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

The tire system is provided the current state of its associated wheel.

Parameters
[in]timecurrent time
[in]wheel_statecurrent state of associated wheel body
[in]terrainreference to the terrain system
[in]collision_typecollision type

Reimplemented from chrono::vehicle::ChTire.

void chrono::vehicle::ChFialaTire::WritePlots ( const std::string &  plFileName,
const std::string &  plTireFormat 
)

Generate basic tire plots.

This function creates a Gnuplot script file with the specified name.