Description

Base class for a Pitman Arm steering subsystem.

Derived from ChSteering, but still an abstract base class.

The steering subsystem is modeled with respect to a right-handed frame with with X pointing towards the front, Y to the left, and Z up (ISO standard).

When attached to a chassis, both an offset and a rotation (as a quaternion) are provided.

#include <ChPitmanArm.h>

Inheritance diagram for chrono::vehicle::ChPitmanArm:
Collaboration diagram for chrono::vehicle::ChPitmanArm:

Public Member Functions

virtual std::string GetTemplateName () const override
 Get the name of the vehicle subsystem template.
 
virtual void Initialize (std::shared_ptr< ChBodyAuxRef > chassis, const ChVector<> &location, const ChQuaternion<> &rotation) override
 Initialize this steering subsystem. More...
 
virtual void AddVisualizationAssets (VisualizationType vis) override
 Add visualization assets for the steering subsystem. More...
 
virtual void RemoveVisualizationAssets () override
 Remove visualization assets for the steering subsystem.
 
virtual void Synchronize (double time, double steering) override
 Update the state of this steering subsystem at the current time. More...
 
virtual double GetMass () const override
 Get the total mass of the steering subsystem.
 
virtual ChVector GetCOMPos () const override
 Get the current global COM location of the steering subsystem.
 
virtual void LogConstraintViolations () override
 Log current constraint violations.
 
- Public Member Functions inherited from chrono::vehicle::ChSteering
 ChSteering (const std::string &name)
 
const ChCoordsysGetPosition () const
 Get the position (location and orientation) of the steering subsystem relative to the chassis reference frame. More...
 
std::shared_ptr< ChBodyGetSteeringLink () const
 Get a handle to the main link of the steering subsystems. More...
 
- 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.
 

Protected Types

enum  PointId {
  STEERINGLINK, PITMANARM, REV, UNIV,
  REVSPH_R, REVSPH_S, TIEROD_PA, TIEROD_IA,
  NUM_POINTS
}
 Identifiers for the various hardpoints. More...
 
enum  DirectionId {
  REV_AXIS, UNIV_AXIS_ARM, UNIV_AXIS_LINK, REVSPH_AXIS,
  NUM_DIRS
}
 Identifiers for the various direction unit vectors. More...
 

Protected Member Functions

 ChPitmanArm (const std::string &name, bool vehicle_frame_inertia=false)
 Protected constructor. More...
 
void SetVehicleFrameInertiaFlag (bool val)
 Indicate whether or not inertia matrices are specified with respect to a vehicle-aligned centroidal frame (flag=true) or with respect to the body centroidal frame (flag=false). More...
 
virtual const ChVector getLocation (PointId which)=0
 Return the location of the specified hardpoint. More...
 
virtual const ChVector getDirection (DirectionId which)=0
 Return the unit vector for the specified direction. More...
 
virtual double getSteeringLinkMass () const =0
 Return the mass of the steering link body.
 
virtual double getPitmanArmMass () const =0
 Return the mass of the Pitman arm body.
 
virtual const ChVectorgetSteeringLinkInertiaMoments () const =0
 Return the moments of inertia of the steering link body.
 
virtual const ChVectorgetSteeringLinkInertiaProducts () const =0
 Return the products of inertia of the steering link body.
 
virtual const ChVectorgetPitmanArmInertiaMoments () const =0
 Return the moments of inertia of the Pitman arm body.
 
virtual const ChVectorgetPitmanArmInertiaProducts () const =0
 Return the products of inertia of the Pitman arm body.
 
virtual double getSteeringLinkRadius () const =0
 Return the radius of the steering link body (visualization only).
 
virtual double getPitmanArmRadius () const =0
 Return the radius of the Pitman arm body (visualization only).
 
virtual double getMaxAngle () const =0
 Return the maximum rotation angle of the revolute joint.
 
- 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

std::shared_ptr< ChBodym_arm
 handle to the Pitman arm body
 
std::shared_ptr< ChLinkMotorRotationAnglem_revolute
 handle to the chassis-arm revolute joint
 
std::shared_ptr< ChLinkRevoluteSphericalm_revsph
 handle to the revolute-spherical joint (idler arm)
 
std::shared_ptr< ChLinkUniversalm_universal
 handle to the arm-link universal joint
 
- Protected Attributes inherited from chrono::vehicle::ChSteering
ChCoordsys m_position
 location and orientation relative to chassis
 
std::shared_ptr< ChBodym_link
 handle to the main steering link
 
- 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

- 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::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::ChPitmanArm::ChPitmanArm ( const std::string &  name,
bool  vehicle_frame_inertia = false 
)
protected

Protected constructor.

Parameters
[in]namename of the subsystem
[in]vehicle_frame_inertiainertia specified in vehicle-aligned centroidal frames?

Member Function Documentation

void chrono::vehicle::ChPitmanArm::AddVisualizationAssets ( VisualizationType  vis)
overridevirtual

Add visualization assets for the steering subsystem.

This default implementation uses primitives.

Reimplemented from chrono::vehicle::ChPart.

virtual const ChVector chrono::vehicle::ChPitmanArm::getDirection ( DirectionId  which)
protectedpure virtual

Return the unit vector for the specified direction.

The returned vector must be expressed in the suspension reference frame.

Implemented in chrono::vehicle::PitmanArm, and chrono::vehicle::hmmwv::HMMWV_PitmanArm.

virtual const ChVector chrono::vehicle::ChPitmanArm::getLocation ( PointId  which)
protectedpure virtual

Return the location of the specified hardpoint.

The returned location must be expressed in the suspension reference frame.

Implemented in chrono::vehicle::PitmanArm, and chrono::vehicle::hmmwv::HMMWV_PitmanArm.

void chrono::vehicle::ChPitmanArm::Initialize ( std::shared_ptr< ChBodyAuxRef chassis,
const ChVector<> &  location,
const ChQuaternion<> &  rotation 
)
overridevirtual

Initialize this steering subsystem.

The steering subsystem is initialized by attaching it to the specified chassis body at the specified location (with respect to and expressed in the reference frame of the chassis) and with specified orientation (with respect to the chassis reference frame).

Parameters
[in]chassishandle to the chassis body
[in]locationlocation relative to the chassis frame
[in]rotationorientation relative to the chassis frame

Implements chrono::vehicle::ChSteering.

void chrono::vehicle::ChPitmanArm::SetVehicleFrameInertiaFlag ( bool  val)
protected

Indicate whether or not inertia matrices are specified with respect to a vehicle-aligned centroidal frame (flag=true) or with respect to the body centroidal frame (flag=false).

Note that this function must be called before Initialize().

void chrono::vehicle::ChPitmanArm::Synchronize ( double  time,
double  steering 
)
overridevirtual

Update the state of this steering subsystem at the current time.

The steering subsystem is provided the current steering driver input (a value between -1 and +1). Positive steering input indicates steering to the left. This function is called during the vehicle update.

Parameters
[in]timecurrent time
[in]steeringcurrent steering input [-1,+1]

Implements chrono::vehicle::ChSteering.