Description

Base class for a Pitman Arm steering subsystem with compliant steering column.

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 <ChPitmanArmShafts.h>

Inheritance diagram for chrono::vehicle::ChPitmanArmShafts:

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Collaboration diagram for chrono::vehicle::ChPitmanArmShafts:

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Public Member Functions
	ChPitmanArmShafts (const std::string &name, bool vehicle_frame_inertia=false, bool rigid_column=false)

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.

void	GetShaftInformation (double time, double &motor_input, double &motor_input_der, std::vector< double > &shaft_angles, std::vector< double > &shaft_velocities, std::vector< double > &constraint_violations, ChVector<> &arm_angular_vel) const
	Return information on steering column shafts and couples (debugging).

Public Member Functions inherited from chrono::vehicle::ChSteering
	ChSteering (const std::string &name)

const ChCoordsys &	GetPosition () const
	Get the position (location and orientation) of the steering subsystem relative to the chassis reference frame.

std::shared_ptr< ChBody >	GetSteeringLink () 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
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 ChVector &	getSteeringLinkInertiaMoments () const =0
	Return the moments of inertia of the steering link body.

virtual const ChVector &	getSteeringLinkInertiaProducts () const =0
	Return the products of inertia of the steering link body.

virtual const ChVector &	getPitmanArmInertiaMoments () const =0
	Return the moments of inertia of the Pitman arm body.

virtual const ChVector &	getPitmanArmInertiaProducts () 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 steering wheel.

virtual double	getGearRatio () const =0
	Return the transmission ratio in the steering column. More...

virtual double	getSteeringCompliance () const =0
	Return the steering column compliance (N.m/rad)

virtual double	getSteeringColumnInertia () const =0
	Return rotational inertia of steering column.

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< ChBody >	m_arm
	handle to the Pitman arm body

std::shared_ptr< ChLinkLockRevolute >	m_revolute
	handle to the chassis-arm revolute joint

std::shared_ptr< ChLinkRevoluteSpherical >	m_revsph
	handle to the revolute-spherical joint (idler arm)

std::shared_ptr< ChLinkUniversal >	m_universal
	handle to the arm-link universal joint

std::shared_ptr< ChShaft >	m_shaft_A
	shaft connected to arm body

std::shared_ptr< ChShaft >	m_shaft_C
	shaft connected to chassis

std::shared_ptr< ChShaft >	m_shaft_A1
	shaft for implementing gear ratio

std::shared_ptr< ChShaft >	m_shaft_C1
	shaft for implementing steering input

std::shared_ptr< ChShaftsBody >	m_shaft_arm
	connection of shaft_A to arm body

std::shared_ptr< ChShaftsBody >	m_shaft_chassis
	connection of shaft_C to chassis body

std::shared_ptr< ChShaftsGear >	m_shaft_gear
	reduction gear between shaft_A and shaft_A1

std::shared_ptr< ChShaftsMotorAngle >	m_shaft_motor
	steering input motor between shaft_C and shaft_C1

std::shared_ptr< ChShaftsGear >	m_rigid_connection
	rigid connection between shaft_A1 and shaft_C1

std::shared_ptr< ChShaftsTorsionSpring >	m_spring_connection
	compliant connection between shaft_A1 and shaft_C1

Protected Attributes inherited from chrono::vehicle::ChSteering
ChCoordsys	m_position
	location and orientation relative to chassis

std::shared_ptr< ChBody >	m_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< 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.

Member Enumeration Documentation

◆ DirectionId

enum chrono::vehicle::ChPitmanArmShafts::DirectionId

protected

Identifiers for the various direction unit vectors.

Enumerator
REV_AXIS	revolute joint
UNIV_AXIS_ARM	universal joint (Pitman arm side)
UNIV_AXIS_LINK	universal joint (steering link side)
REVSPH_AXIS	revolute joint for idler arm

◆ PointId

enum chrono::vehicle::ChPitmanArmShafts::PointId

protected

Identifiers for the various hardpoints.

Enumerator
STEERINGLINK	steering link location (com)
PITMANARM	Pitman arm location (com)
REV	location of joint between Pitman arm and chassis
UNIV	location of joint between Pitman arm and steering link
REVSPH_R	location of revolute joint for the idler arm
REVSPH_S	location of spherical joint for the idler arm
TIEROD_PA	tierod connection point (Pitman arm side)
TIEROD_IA	tierod connection point (idler arm side)

Constructor & Destructor Documentation

◆ ChPitmanArmShafts()

chrono::vehicle::ChPitmanArmShafts::ChPitmanArmShafts	(	const std::string &	name,
		bool	vehicle_frame_inertia = `false`,
		bool	rigid_column = `false`
	)

Parameters

[in]	name	name of the subsystem
[in]	vehicle_frame_inertia	inertia specified in vehicle-aligned centroidal frames?
[in]	rigid_column	force a rigid steering column

Member Function Documentation

◆ AddVisualizationAssets()

void chrono::vehicle::ChPitmanArmShafts::AddVisualizationAssets ( VisualizationType vis )

overridevirtual

Add visualization assets for the steering subsystem.

This default implementation uses primitives.

Reimplemented from chrono::vehicle::ChPart.

◆ getDirection()

virtual const ChVector chrono::vehicle::ChPitmanArmShafts::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::hmmwv::HMMWV_PitmanArmShafts.

◆ getGearRatio()

virtual double chrono::vehicle::ChPitmanArmShafts::getGearRatio ( ) const

protectedpure virtual

Return the transmission ratio in the steering column.

This value must be larger than 1.

Implemented in chrono::vehicle::hmmwv::HMMWV_PitmanArmShafts.

◆ getLocation()

virtual const ChVector chrono::vehicle::ChPitmanArmShafts::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::hmmwv::HMMWV_PitmanArmShafts.

◆ Initialize()

void chrono::vehicle::ChPitmanArmShafts::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]	chassis	handle to the chassis body
[in]	location	location relative to the chassis frame
[in]	rotation	orientation relative to the chassis frame

Implements chrono::vehicle::ChSteering.

◆ SetVehicleFrameInertiaFlag()

void chrono::vehicle::ChPitmanArmShafts::SetVehicleFrameInertiaFlag ( bool val )

inlineprotected

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().

◆ Synchronize()

void chrono::vehicle::ChPitmanArmShafts::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]	time	current time
[in]	steering	current steering input [-1,+1]

Implements chrono::vehicle::ChSteering.

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

/builds/uwsbel/chrono/src/chrono_vehicle/wheeled_vehicle/steering/ChPitmanArmShafts.h
/builds/uwsbel/chrono/src/chrono_vehicle/wheeled_vehicle/steering/ChPitmanArmShafts.cpp

Description

Public Member Functions

Protected Types

Protected Member Functions

Protected Attributes

Additional Inherited Members

Member Enumeration Documentation

◆ DirectionId

◆ PointId

Constructor & Destructor Documentation

◆ ChPitmanArmShafts()

Member Function Documentation

◆ AddVisualizationAssets()

◆ getDirection()

◆ getGearRatio()

◆ getLocation()

◆ Initialize()

◆ SetVehicleFrameInertiaFlag()

◆ Synchronize()