Description

Base class for a multi-link suspension modeled with bodies and constraints.

Derived from ChSuspension, but still an abstract base class.

The suspension subsystem is modeled with respect to a right-handed frame, with X pointing towards the front, Y to the left, and Z up (ISO standard). The suspension reference frame is assumed to be always aligned with that of the vehicle. When attached to a chassis, only an offset is provided.

All point locations are assumed to be given for the left half of the suspension and will be mirrored (reflecting the y coordinates) to construct the right side.

#include <ChMultiLink.h>

Inheritance diagram for chrono::vehicle::ChMultiLink:

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Collaboration diagram for chrono::vehicle::ChMultiLink:

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

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

virtual bool	IsSteerable () const final override
	Specify whether or not this suspension can be steered.

virtual bool	IsIndependent () const final override
	Specify whether or not this is an independent suspension.

virtual void	Initialize (std::shared_ptr< ChChassis > chassis, std::shared_ptr< ChSubchassis > subchassis, std::shared_ptr< ChSteering > steering, const ChVector<> &location, double left_ang_vel=0, double right_ang_vel=0) override
	Initialize this suspension subsystem. More...

virtual void	AddVisualizationAssets (VisualizationType vis) override
	Add visualization assets for the suspension subsystem. More...

virtual void	RemoveVisualizationAssets () override
	Remove visualization assets for the suspension subsystem.

virtual double	GetMass () const override
	Get the total mass of the suspension subsystem.

virtual ChVector	GetCOMPos () const override
	Get the current global COM location of the suspension subsystem.

virtual double	GetTrack () override
	Get the wheel track for the suspension subsystem.

std::shared_ptr< ChLinkTSDA >	GetSpring (VehicleSide side) const
	Get a handle to the specified spring element.

std::shared_ptr< ChLinkTSDA >	GetShock (VehicleSide side) const
	Get a handle to the specified shock (damper) element.

virtual ChSuspension::Force	ReportSuspensionForce (VehicleSide side) const override
	Return current suspension forces (spring and shock) on the specified side.

double	GetSpringForce (VehicleSide side) const
	Get the force in the spring element.

double	GetSpringLength (VehicleSide side) const
	Get the current length of the spring element.

double	GetSpringDeformation (VehicleSide side) const
	Get the current deformation of the spring element.

double	GetShockForce (VehicleSide side) const
	Get the force in the shock (damper) element.

double	GetShockLength (VehicleSide side) const
	Get the current length of the shock (damper) element.

double	GetShockVelocity (VehicleSide side) const
	Get the current deformation velocity of the shock (damper) element.

virtual std::shared_ptr< ChBody >	GetAntirollBody (VehicleSide side) const override
	Specify the suspension body on the specified side to attach a possible antirollbar subsystem. More...

virtual void	LogConstraintViolations (VehicleSide side) override
	Log current constraint violations.

void	LogHardpointLocations (const ChVector<> &ref, bool inches=false)
	Log the locations of all hardpoints. More...

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

const ChVector &	GetLocation () const
	Get the location of the suspension subsystem relative to the chassis reference frame. More...

std::shared_ptr< ChBody >	GetSpindle (VehicleSide side) const
	Get a handle to the spindle body on the specified side.

std::shared_ptr< ChShaft >	GetAxle (VehicleSide side) const
	Get a handle to the axle shaft on the specified side.

std::shared_ptr< ChLinkLockRevolute >	GetRevolute (VehicleSide side) const
	Get a handle to the revolute joint on the specified side.

const ChVector &	GetSpindlePos (VehicleSide side) const
	Get the global location of the spindle on the specified side.

ChQuaternion	GetSpindleRot (VehicleSide side) const
	Get the orientation of the spindle body on the specified side. More...

const ChVector &	GetSpindleLinVel (VehicleSide side) const
	Get the linear velocity of the spindle body on the specified side. More...

ChVector	GetSpindleAngVel (VehicleSide side) const
	Get the angular velocity of the spindle body on the specified side. More...

double	GetAxleSpeed (VehicleSide side) const
	Get the angular speed of the axle on the specified side.

void	Synchronize ()
	Synchronize this suspension subsystem. More...

void	ApplyAxleTorque (VehicleSide side, double torque)
	Apply the provided motor torque. More...

virtual double	getSpindleRadius () const =0
	Return the radius of the spindle body (visualization only).

virtual double	getSpindleWidth () const =0
	Return the width of the spindle body (visualization only).

virtual std::shared_ptr< ChBody >	GetBrakeBody (VehicleSide side) const
	Specify the body on the specified side for a possible connection to brake subsystem. More...

void	ApplyParkingBrake (bool brake)
	Simple model of a parking brake.

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.

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 { SPINDLE, UPRIGHT, UA_F, UA_B, UA_U, UA_CM, LAT_C, LAT_U, LAT_CM, TL_C, TL_U, TL_CM, SHOCK_C, SHOCK_L, SPRING_C, SPRING_L, TIEROD_C, TIEROD_U, NUM_POINTS }
	Identifiers for the various hardpoints. More...

enum	DirectionId { UNIV_AXIS_LINK_TL, UNIV_AXIS_CHASSIS_TL, UNIV_AXIS_LINK_LAT, UNIV_AXIS_CHASSIS_LAT, NUM_DIRS }
	Identifiers for the various vectors. More...

Protected Member Functions
virtual const ChVector	getLocation (PointId which)=0
	Return the location of the specified hardpoint. More...

virtual const ChVector	getDirection (DirectionId which)=0
	Return the vector of the specified direction.

virtual double	getSpindleMass () const =0
	Return the mass of the spindle body.

virtual double	getUpperArmMass () const =0
	Return the mass of the upper arm body.

virtual double	getLateralMass () const =0
	Return the mass of the lateral body.

virtual double	getTrailingLinkMass () const =0
	Return the mass of the trailing link body.

virtual double	getUprightMass () const =0
	Return the mass of the upright body.

virtual const ChVector &	getSpindleInertia () const =0
	Return the moments of inertia of the spindle body.

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

virtual const ChVector &	getLateralInertia () const =0
	Return the moments of inertia of the lateral body.

virtual const ChVector &	getTrailingLinkInertia () const =0
	Return the moments of inertia of the trailing link body.

virtual const ChVector &	getUprightInertia () const =0
	Return the moments of inertia of the upright body.

virtual double	getAxleInertia () const =0
	Return the inertia of the axle shaft.

virtual double	getUpperArmRadius () const =0
	Return the radius of the upper arm body (visualization only).

virtual double	getLateralRadius () const =0
	Return the radius of the lateral body (visualization only).

virtual double	getTrailingLinkRadius () const =0
	Return the radius of the trailing link body (visualization only).

virtual double	getUprightRadius () const =0
	Return the radius of the upright body (visualization only).

virtual double	getSpringRestLength () const =0
	Return the free (rest) length of the spring element.

virtual std::shared_ptr< ChLinkTSDA::ForceFunctor >	getSpringForceFunctor () const =0
	Return the functor object for spring force.

virtual std::shared_ptr< ChLinkTSDA::ForceFunctor >	getShockForceFunctor () const =0
	Return the functor object for shock force.

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_upright [2]
	handles to the upright bodies (left/right)

std::shared_ptr< ChBody >	m_upperArm [2]
	handles to the upper arm bodies (left/right)

std::shared_ptr< ChBody >	m_lateral [2]
	handles to the lateral bodies (left/right)

std::shared_ptr< ChBody >	m_trailingLink [2]
	handles to the trailing link bodies (left/right)

std::shared_ptr< ChLinkLockRevolute >	m_revoluteUA [2]
	handles to the chassis-UA revolute joints (left/right)

std::shared_ptr< ChLinkLockSpherical >	m_sphericalUA [2]
	handles to the upright-UA spherical joints (left/right)

std::shared_ptr< ChLinkUniversal >	m_universalLateralChassis [2]
	handles to the chassis-lateral universal joints (left/right)

std::shared_ptr< ChLinkLockSpherical >	m_sphericalLateralUpright [2]
	handles to the upright-lateral spherical joints (left/right)

std::shared_ptr< ChLinkUniversal >	m_universalTLChassis [2]
	handles to the chassis-trailing link universal joints (left/right)

std::shared_ptr< ChLinkLockSpherical >	m_sphericalTLUpright [2]
	handles to the upright-trailing link spherical joints (left/right)

std::shared_ptr< ChLinkDistance >	m_distTierod [2]
	handles to the tierod distance constraints (left/right)

std::shared_ptr< ChLinkTSDA >	m_shock [2]
	handles to the spring links (left/right)

std::shared_ptr< ChLinkTSDA >	m_spring [2]
	handles to the shock links (left/right)

Protected Attributes inherited from chrono::vehicle::ChSuspension
ChVector	m_location
	location relative to chassis

std::shared_ptr< ChBody >	m_spindle [2]
	handles to spindle bodies

std::shared_ptr< ChShaft >	m_axle [2]
	handles to axle shafts

std::shared_ptr< ChShaftsBody >	m_axle_to_spindle [2]
	handles to spindle-shaft connectors

std::shared_ptr< ChLinkLockRevolute >	m_revolute [2]
	handles to spindle revolute joints

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

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::ChMultiLink::DirectionId

protected

Identifiers for the various vectors.

Enumerator
UNIV_AXIS_LINK_TL	universal joint (trailing link, link side)
UNIV_AXIS_CHASSIS_TL	universal joint (trailing link, chassis side)
UNIV_AXIS_LINK_LAT	universal joint (lateral, link side)
UNIV_AXIS_CHASSIS_LAT	universal joint (lateral, chassis side)

◆ PointId

enum chrono::vehicle::ChMultiLink::PointId

protected

Identifiers for the various hardpoints.

Enumerator
SPINDLE	spindle location
UPRIGHT	upright location
UA_F	upper arm, chassis front
UA_B	upper arm, chassis back
UA_U	upper arm, upright
UA_CM	upper arm, center of mass
LAT_C	lateral, chassis
LAT_U	lateral, upright
LAT_CM	lateral, center of mass
TL_C	trailing link, chassis
TL_U	trailing link, upright
TL_CM	trailing link, center of mass
SHOCK_C	shock, chassis
SHOCK_L	shock, trailing link
SPRING_C	spring, chassis
SPRING_L	spring, trailing link
TIEROD_C	tierod, chassis
TIEROD_U	tierod, upright

Constructor & Destructor Documentation

◆ ChMultiLink()

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

Parameters

[in] name name of the subsystem

Member Function Documentation

◆ AddVisualizationAssets()

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

overridevirtual

Add visualization assets for the suspension subsystem.

This default implementation uses primitives.

Reimplemented from chrono::vehicle::ChSuspension.

◆ GetAntirollBody()

virtual std::shared_ptr<ChBody> chrono::vehicle::ChMultiLink::GetAntirollBody ( VehicleSide side ) const

inlineoverridevirtual

Specify the suspension body on the specified side to attach a possible antirollbar subsystem.

Return the corresponding trailing link.

Reimplemented from chrono::vehicle::ChSuspension.

◆ getLocation()

virtual const ChVector chrono::vehicle::ChMultiLink::getLocation ( PointId which )

protectedpure virtual

Return the location of the specified hardpoint.

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

◆ Initialize()

void chrono::vehicle::ChMultiLink::Initialize	(	std::shared_ptr< ChChassis >	chassis,
		std::shared_ptr< ChSubchassis >	subchassis,
		std::shared_ptr< ChSteering >	steering,
		const ChVector<> &	location,
		double	left_ang_vel = `0`,
		double	right_ang_vel = `0`
	)

overridevirtual

Initialize this suspension subsystem.

The suspension subsystem is initialized by attaching it to the specified chassis and (if provided) to the specified subchassis, at the specified location (with respect to and expressed in the reference frame of the chassis). It is assumed that the suspension reference frame is always aligned with the chassis reference frame. If a steering subsystem is provided, the suspension tierods are to be attached to the steering's central link body (steered suspension); otherwise they are to be attached to the chassis (non-steered suspension).

Parameters

[in]	chassis	associated chassis subsystem
[in]	subchassis	associated subchassis subsystem (may be null)
[in]	steering	associated steering subsystem (may be null)
[in]	location	location relative to the chassis frame
[in]	left_ang_vel	initial angular velocity of left wheel
[in]	right_ang_vel	initial angular velocity of right wheel

Implements chrono::vehicle::ChSuspension.

◆ LogHardpointLocations()

void chrono::vehicle::ChMultiLink::LogHardpointLocations	(	const ChVector<> &	ref,
		bool	inches = `false`
	)

Log the locations of all hardpoints.

The reported locations are expressed in the suspension reference frame. By default, these values are reported in SI units (meters), but can be optionally reported in inches.

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

/builds/uwsbel/chrono/src/chrono_vehicle/wheeled_vehicle/suspension/ChMultiLink.h
/builds/uwsbel/chrono/src/chrono_vehicle/wheeled_vehicle/suspension/ChMultiLink.cpp