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:
Collaboration diagram for chrono::vehicle::ChTire:

Public Types

enum  CollisionType { SINGLE_POINT, FOUR_POINTS, ENVELOPE }
 

Public Member Functions

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...
 
void SetPressure (double pressure)
 Set the internal tire pressure [Pa]. More...
 
double GetPressure () const
 Get the internal tire pressure [Pa].
 
virtual double GetRadius () const =0
 Get the tire radius.
 
virtual double GetWidth () const =0
 Get the tire width.
 
virtual double GetTireMass () const =0
 Return the tire mass.
 
virtual ChVector3d GetTireInertia () const =0
 Return the tire moments of inertia (in the tire centroidal frame).
 
virtual TerrainForce ReportTireForce (ChTerrain *terrain) const =0
 Report the tire force and moment. More...
 
virtual TerrainForce ReportTireForceLocal (ChTerrain *terrain, ChCoordsys<> &tire_frame) const =0
 Get the tire force and moment expressed in the tire frame. 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.
 
const std::string & GetMeshFilename () const
 Get the name of the Wavefront file with tire visualization mesh. More...
 
virtual void Initialize (std::shared_ptr< ChWheel > wheel)
 Initialize this tire subsystem by associating it to an existing wheel subsystem.
 
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
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.
 
bool IsInitialized () const
 Return flag indicating whether or not the part is fully constructed.
 
double GetMass () const
 Get the subsystem mass. More...
 
const ChFrameGetCOMFrame () const
 Get the current subsystem COM frame (relative to and expressed in the subsystem's reference frame). More...
 
const ChMatrix33GetInertia () const
 Get the current subsystem inertia (relative to the subsystem COM frame). More...
 
const ChFrameGetTransform () const
 Get the current subsystem position relative to the global frame. More...
 
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.
 
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 ChVector3d 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 ChVector3d &moments, const ChVector3d &products, const ChMatrix33<> &vehicle_rot, const ChMatrix33<> &body_rot)
 Utility function for transforming inertia tensors between centroidal frames. More...
 

Protected Member Functions

 ChTire (const std::string &name)
 Construct a tire subsystem with given name.
 
void CalculateKinematics (const WheelState &wheel_state, const ChCoordsys<> &tire_frame)
 Calculate kinematics quantities based on the given state of the associated wheel body. More...
 
double GetOffset () const
 Get offset from spindle center. More...
 
virtual double GetAddedMass () const =0
 Get the mass added to the associated spindle body. More...
 
virtual ChVector3d GetAddedInertia () const =0
 Get the inertia added to the associated spindle body. More...
 
virtual TerrainForce GetTireForce () const =0
 Get the tire force and moment. More...
 
std::shared_ptr< ChVisualShapeTriangleMeshAddVisualizationMesh (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...
 
- Protected Member Functions inherited from chrono::vehicle::ChPart
 ChPart (const std::string &name)
 Construct a vehicle subsystem with the specified name.
 
virtual void InitializeInertiaProperties ()=0
 Initialize subsystem inertia properties. More...
 
virtual void UpdateInertiaProperties ()=0
 Update subsystem inertia properties. More...
 
void AddMass (double &mass)
 Add this subsystem's mass. More...
 
void AddInertiaProperties (ChVector3d &com, ChMatrix33<> &inertia)
 Add this subsystem's inertia properties. More...
 
virtual void Create (const rapidjson::Document &d)
 Create a vehicle subsystem from JSON data. More...
 
void ExportBodyList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChBody >> bodies) const
 Export the list of bodies to the specified JSON document.
 
void ExportShaftList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChShaft >> shafts) const
 Export the list of shafts to the specified JSON document.
 
void ExportJointList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChLink >> joints) const
 Export the list of joints to the specified JSON document.
 
void ExportCouplesList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChShaftsCouple >> couples) const
 Export the list of shaft couples to the specified JSON document.
 
void ExportMarkerList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChMarker >> markers) const
 Export the list of markers to the specified JSON document.
 
void ExportLinSpringList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChLinkTSDA >> springs) const
 Export the list of translational springs to the specified JSON document.
 
void ExportRotSpringList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChLinkRSDA >> springs) const
 Export the list of rotational springs to the specified JSON document.
 
void ExportBodyLoadList (rapidjson::Document &jsonDocument, std::vector< std::shared_ptr< ChLoadBodyBody >> loads) const
 Export the list of body-body loads to the specified JSON document.
 

Static Protected Member Functions

static bool DiscTerrainCollision (CollisionType method, const ChTerrain &terrain, const ChVector3d &disc_center, const ChVector3d &disc_normal, double disc_radius, double width, const ChFunctionInterp &areaDep, ChCoordsys<> &contact, double &depth, float &mu)
 Perform disc-terrain collision detection, using the specified method. More...
 
static void ConstructAreaDepthTable (double disc_radius, ChFunctionInterp &areaDep)
 Utility function to construct a loopkup table for penetration depth as function of intersection area, for a given tire radius. More...
 
static bool DiscTerrainCollision1pt (const ChTerrain &terrain, const ChVector3d &disc_center, const ChVector3d &disc_normal, double disc_radius, ChCoordsys<> &contact, double &depth, float &mu)
 Perform disc-terrain collision detection. More...
 
static bool DiscTerrainCollision4pt (const ChTerrain &terrain, const ChVector3d &disc_center, const ChVector3d &disc_normal, double disc_radius, double width, ChCoordsys<> &contact, double &depth, float &mu)
 Perform disc-terrain collision detection considering the curvature of the road surface. More...
 
static bool DiscTerrainCollisionEnvelope (const ChTerrain &terrain, const ChVector3d &disc_center, const ChVector3d &disc_normal, double disc_radius, double width, const ChFunctionInterp &areaDep, ChCoordsys<> &contact, double &depth, float &mu)
 Collsion algorithm based on a paper of J. More...
 
- Static Protected Member Functions inherited from chrono::vehicle::ChPart
static void RemoveVisualizationAssets (std::shared_ptr< ChPhysicsItem > item)
 Erase all visual shapes from the visual model associated with the specified physics item (if any).
 
static void RemoveVisualizationAsset (std::shared_ptr< ChPhysicsItem > item, std::shared_ptr< ChVisualShape > shape)
 Erase the given shape from the visual model associated with the specified physics item (if any).
 

Protected Attributes

std::shared_ptr< ChWheelm_wheel
 associated wheel subsystem
 
double m_stepsize
 tire integration step size (if applicable)
 
double m_pressure
 internal tire pressure
 
CollisionType m_collision_type
 method used for tire-terrain collision
 
std::string m_vis_mesh_file
 name of OBJ file for visualization of this tire (may be empty)
 
double m_slip_angle
 
double m_longitudinal_slip
 
double m_camber_angle
 
- Protected Attributes inherited from chrono::vehicle::ChPart
std::string m_name
 subsystem name
 
bool m_initialized
 specifies whether ot not the part is fully constructed
 
bool m_output
 specifies whether or not output is generated for this subsystem
 
std::shared_ptr< ChPartm_parent
 parent subsystem (empty if parent is vehicle)
 
double m_mass
 subsystem mass
 
ChMatrix33 m_inertia
 inertia tensor (relative to subsystem COM)
 
ChFrame m_com
 COM frame (relative to subsystem reference frame)
 
ChFrame m_xform
 subsystem frame expressed in the global frame
 

Friends

class ChWheel
 
class ChWheeledVehicle
 
class ChWheeledTrailer
 

Member Function Documentation

◆ AddVisualizationMesh()

std::shared_ptr< ChVisualShapeTriangleMesh > 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 ( const WheelState wheel_state,
const ChCoordsys<> &  tire_frame 
)
protected

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

Parameters
[in]wheel_statecurrent state of associated wheel body
[in]tire_frametire contact frame

◆ ConstructAreaDepthTable()

void chrono::vehicle::ChTire::ConstructAreaDepthTable ( double  disc_radius,
ChFunctionInterp 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 ( CollisionType  method,
const ChTerrain terrain,
const ChVector3d disc_center,
const ChVector3d disc_normal,
double  disc_radius,
double  width,
const ChFunctionInterp areaDep,
ChCoordsys<> &  contact,
double &  depth,
float &  mu 
)
staticprotected

Perform disc-terrain collision detection, using the specified method.

Parameters
[in]methodtire-terrain collision detection method
[in]terrainreference to terrain system
[in]disc_centerglobal location of the disc center
[in]disc_normaldisc normal, expressed in the global frame
[in]disc_radiusdisc radius
[in]widthtire width
[in]areaDeplookup table to calculate depth from intersection area
[out]contactcontact coordinate system (relative to the global frame)
[out]depthpenetration depth (positive if contact occurred)
[out]mucoefficient of friction at contact

◆ DiscTerrainCollision1pt()

bool chrono::vehicle::ChTire::DiscTerrainCollision1pt ( const ChTerrain terrain,
const ChVector3d disc_center,
const ChVector3d disc_normal,
double  disc_radius,
ChCoordsys<> &  contact,
double &  depth,
float &  mu 
)
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]terrainreference to terrain system
[in]disc_centerglobal location of the disc center
[in]disc_normaldisc normal, expressed in the global frame
[in]disc_radiusdisc radius
[out]contactcontact coordinate system (relative to the global frame)
[out]depthpenetration depth (positive if contact occurred)
[out]mucoefficient of friction at contact

◆ DiscTerrainCollision4pt()

bool chrono::vehicle::ChTire::DiscTerrainCollision4pt ( const ChTerrain terrain,
const ChVector3d disc_center,
const ChVector3d disc_normal,
double  disc_radius,
double  width,
ChCoordsys<> &  contact,
double &  depth,
float &  mu 
)
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]terrainreference to terrain system
[in]disc_centerglobal location of the disc center
[in]disc_normaldisc normal, expressed in the global frame
[in]disc_radiusdisc radius
[in]widthtire width
[out]contactcontact coordinate system (relative to the global frame)
[out]depthpenetration depth (positive if contact occurred)
[out]mucoefficient of friction at contact

◆ DiscTerrainCollisionEnvelope()

bool chrono::vehicle::ChTire::DiscTerrainCollisionEnvelope ( const ChTerrain terrain,
const ChVector3d disc_center,
const ChVector3d disc_normal,
double  disc_radius,
double  width,
const ChFunctionInterp areaDep,
ChCoordsys<> &  contact,
double &  depth,
float &  mu 
)
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]terrainreference to terrain system
[in]disc_centerglobal location of the disc center
[in]disc_normaldisc normal, expressed in the global frame
[in]disc_radiusdisc radius
[in]widthtire width
[in]areaDeplookup table to calculate depth from intersection area
[out]contactcontact coordinate system (relative to the global frame)
[out]depthpenetration depth (positive if contact occurred)
[out]mucoefficient of friction at contact

◆ EstimateInertia()

ChVector3d 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_widthtire width [mm]
aspect_ratioaspect ratio: height to width [percentage]
rim_diameterrim diameter [in]
tire_massmass of the tire [kg]
t_factortread to sidewall thickness factor

◆ GetAddedInertia()

virtual ChVector3d chrono::vehicle::ChTire::GetAddedInertia ( ) const
protectedpure virtual

Get the inertia added to the associated spindle body.

Certain tires (e.g., those FEA-based) have their own physical representation and hence do not add mass and inertia to the spindle body. All others increment the spindle body moments of inertia by the amount reported by this function.

Implemented in chrono::vehicle::ChDeformableTire, and chrono::vehicle::ChRigidTire.

◆ GetAddedMass()

virtual double chrono::vehicle::ChTire::GetAddedMass ( ) const
protectedpure virtual

Get the mass added to the associated spindle body.

Certain tires (e.g., those FEA-based) have their own physical representation and hence do not add mass and inertia to the spindle body. All others increment the spindle body mass by the amount repoirted by this function.

Implemented in chrono::vehicle::ChDeformableTire, and chrono::vehicle::ChRigidTire.

◆ GetCamberAngle()

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

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

Note that this is a "dynamic" or "effective" camber angle, defined as the angle of the wheel from a plane normal to the current tire contact patch. The return value is in radians. A positive value corresponds to the upper side tipping to the left, while a negative value indicates the upper side tipping to the right.

◆ GetLongitudinalSlip()

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

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

A positive value corresponds to a driving wheel, while a negative sign indicates braking.

◆ GetMeshFilename()

const std::string& chrono::vehicle::ChTire::GetMeshFilename ( ) const
inline

Get the name of the Wavefront file with tire visualization mesh.

An empty string is returned if no mesh was specified.

◆ 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 with a positive sign for a left turn and a negative sign for a 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. The return application point, force, and moment are assumed to be expressed in the global reference frame. 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.

Implemented in chrono::vehicle::ChDeformableTire, chrono::vehicle::ChRigidTire, and chrono::vehicle::ChForceElementTire.

◆ 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. The return application point, force, and moment are assumed to be expressed in the global reference frame.

Implemented in chrono::vehicle::ChDeformableTire, chrono::vehicle::ChRigidTire, and chrono::vehicle::ChForceElementTire.

◆ ReportTireForceLocal()

virtual TerrainForce chrono::vehicle::ChTire::ReportTireForceLocal ( ChTerrain terrain,
ChCoordsys<> &  tire_frame 
) const
pure virtual

Get the tire force and moment expressed in the tire frame.

The tire frame has its origin in the contact patch, the X axis in the tire heading direction and the Z axis in the terrain normal at the contact point. If the tire is not in contact, the tire frame is not set and the function returns zero force and moment.

Implemented in chrono::vehicle::ChDeformableTire, chrono::vehicle::ChRigidTire, and chrono::vehicle::ChForceElementTire.

◆ SetCollisionType()

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

Set the collision type for tire-terrain interaction.

Default: SINGLE_POINT

◆ SetPressure()

void chrono::vehicle::ChTire::SetPressure ( double  pressure)
inline

Set the internal tire pressure [Pa].

Default value: 0. Derived classes (concrete tire models) may or may not use this setting.

◆ 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.

A derived class should also set the current slip, longitudinal slip, and camber angle.

Reimplemented in chrono::vehicle::ChPac02Tire, chrono::vehicle::ChTMeasyTire, chrono::vehicle::ChTMsimpleTire, chrono::vehicle::ChPac89Tire, chrono::vehicle::ChRigidTire, and chrono::vehicle::ChFialaTire.


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