Description

Base class for a leaf-spring solid axle suspension.

Derived from ChSuspension, but still an abstract base class.

This implementation follows the SAE Spring Design Handbook, which shows the use of a kinematic leafspring model made of three links. The three 'links' are front leaf / clamp / rear leaf / shackle. The clamp is considered as rigid and part of the axle tube in the SAE book. In this chrono model we had to split the clamp into two separate bodies clampA and clampB. Both are connected via a rotational joint around Z. This was necessary because we need to mimic the lateral compliance of the leafspring. The leaves (front and rear) are connected to clampA rsp. clampB via rotational joints around Y. The frontleaf also connects to the chassis with a spherical joint, while the rearleaf connects to the shackle body with a sperical joint. The shackle body connects to the chassis via a rotational joint around Y.

The vertical stiffnesses are simulated by the rotational springs of the frontleaf and the rearleaf while the lateral stiffnesses are simulated by the rotational joints of the clamp bodies.

For the stiffness parameters the user can take the desired translatoric vertical stiffness devided by two (we have two leaves). The preload can be set as a vertical force devided by two. The conversion to the rotary setup is made automatically.

The SAE model allows to consider the correct axle movement due to wheel travel. It is possible to consider the tie-up mode due to longitudinal forces (breaking). It also possible to use different stiffnesses for the front leaf and the rear leaf, many practical designs use this to avoid tie-up problems.

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 <ChSAELeafspringAxle.h>

Inheritance diagram for chrono::vehicle::ChSAELeafspringAxle:
Collaboration diagram for chrono::vehicle::ChSAELeafspringAxle:

Public Member Functions

 ChSAELeafspringAxle (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 GetTrack () override
 Get the wheel track for the suspension subsystem.
 
std::shared_ptr< ChLinkTSDAGetSpring (VehicleSide side) const
 Get a handle to the specified spring element.
 
std::shared_ptr< ChLinkTSDAGetShock (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 void LogConstraintViolations (VehicleSide side) override
 Log current constraint violations.
 
void LogHardpointLocations (const ChVector<> &ref, bool inches=false)
 
- Public Member Functions inherited from chrono::vehicle::ChSuspension
const ChVectorGetRelPosition () const
 Get the location of the suspension subsystem relative to the associated chassis reference frame. More...
 
std::shared_ptr< ChBodyGetSpindle (VehicleSide side) const
 Get a handle to the spindle body on the specified side.
 
std::shared_ptr< ChShaftGetAxle (VehicleSide side) const
 Get a handle to the axle shaft on the specified side.
 
std::shared_ptr< ChLinkLockRevoluteGetRevolute (VehicleSide side) const
 Get a handle to the revolute joint on the specified side.
 
const ChVectorGetSpindlePos (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 ChVectorGetSpindleLinVel (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< ChBodyGetAntirollBody (VehicleSide side) const
 Specify the suspension body on the specified side to attach a possible antirollbar subsystem. More...
 
virtual std::shared_ptr< ChBodyGetBrakeBody (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
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.
 
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 SetOutput (bool state)
 Enable/disable output for this subsystem.
 
bool OutputEnabled () const
 Return the output state for this subsystem.
 

Protected Types

enum  PointId {
  SHOCK_A, SHOCK_C, SPRING_A, SPRING_C,
  SPINDLE, CLAMP_A, CLAMP_B, FRONT_HANGER,
  REAR_HANGER, SHACKLE, NUM_POINTS
}
 Identifiers for the various hardpoints. More...
 

Protected Member Functions

virtual void InitializeInertiaProperties () override
 Initialize subsystem inertia properties. More...
 
virtual void UpdateInertiaProperties () override
 Update subsystem inertia properties. More...
 
virtual const ChVector getLocation (PointId which)=0
 Return the location of the specified hardpoint. More...
 
virtual const ChVector getAxleTubeCOM () const =0
 Return the center of mass of the axle tube.
 
virtual double getAxleTubeMass () const =0
 Return the mass of the axle tube body.
 
virtual double getSpindleMass () const =0
 Return the mass of the spindle body.
 
virtual double getFrontLeafMass () const =0
 Return the mass of the frontleaf body.
 
virtual double getRearLeafMass () const =0
 Return the mass of the rearleaf body.
 
virtual double getClampMass () const =0
 Return the mass of the half clamp body.
 
virtual double getShackleMass () const =0
 Return the mass of the shackle body.
 
virtual double getAxleTubeRadius () const =0
 Return the radius of the axle tube body (visualization only).
 
virtual const ChVectorgetAxleTubeInertia () const =0
 Return the moments of inertia of the axle tube body.
 
virtual const ChVectorgetSpindleInertia () const =0
 Return the moments of inertia of the spindle body.
 
virtual const ChVectorgetFrontLeafInertia () const =0
 Return the moments of inertia of the frontleaf body.
 
virtual const ChVectorgetRearLeafInertia () const =0
 Return the moments of inertia of the frontleaf body.
 
virtual const ChVectorgetClampInertia () const =0
 Return the moments of inertia of the half leafclamp body.
 
virtual const ChVectorgetShackleInertia () const =0
 Return the moments of inertia of the shackle body.
 
virtual double getAxleInertia () const =0
 Return the inertia of the axle shaft.
 
virtual double getSpringRestLength () const =0
 Return the free (rest) length of the auxiliary spring element.
 
virtual std::shared_ptr< ChLinkTSDA::ForceFunctorgetSpringForceFunctor () const =0
 Return the functor object for auxiliary spring force.
 
virtual std::shared_ptr< ChLinkTSDA::ForceFunctorgetShockForceFunctor () const =0
 Return the functor object for auxiliary shock force.
 
virtual std::shared_ptr< ChLinkRSDA::TorqueFunctorgetLatTorqueFunctorA () const =0
 
virtual std::shared_ptr< ChLinkRSDA::TorqueFunctorgetLatTorqueFunctorB () const =0
 
virtual std::shared_ptr< ChLinkRSDA::TorqueFunctorgetVertTorqueFunctorA () const =0
 
virtual std::shared_ptr< ChLinkRSDA::TorqueFunctorgetVertTorqueFunctorB () const =0
 
virtual std::shared_ptr< ChVehicleBushingDatagetShackleBushingData () const
 Return stiffness and damping data for the shackle bushing. More...
 
virtual std::shared_ptr< ChVehicleBushingDatagetClampBushingData () const
 Return stiffness and damping data for the clamp bushing. More...
 
virtual std::shared_ptr< ChVehicleBushingDatagetLeafspringBushingData () const
 Return stiffness and damping data for the leafspring bushing. More...
 
- Protected Member Functions inherited from chrono::vehicle::ChSuspension
 ChSuspension (const std::string &name)
 Construct a suspension subsystem with given name.
 
- Protected Member Functions inherited from chrono::vehicle::ChPart
 ChPart (const std::string &name)
 Construct a vehicle subsystem with the specified name.
 
void AddMass (double &mass)
 Add this subsystem's mass. More...
 
void AddInertiaProperties (ChVector<> &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...
 

Protected Attributes

std::shared_ptr< ChBodym_axleTube
 axle tube body
 
std::shared_ptr< ChLinkTSDAm_shock [2]
 spring links (L/R)
 
std::shared_ptr< ChLinkTSDAm_spring [2]
 shock links (L/R)
 
std::shared_ptr< ChBodym_shackle [2]
 shackle bodies
 
std::shared_ptr< ChVehicleJointm_shackleRev [2]
 chassis-shackle rotational joint
 
std::shared_ptr< ChBodym_frontleaf [2]
 frontleaf bodies
 
std::shared_ptr< ChLinkLockSphericalm_frontleafSph [2]
 frontleaf-chassis spherical joint
 
std::shared_ptr< ChVehicleJointm_frontleafRev [2]
 frontleaf-clampA rotational joint
 
std::shared_ptr< ChBodym_rearleaf [2]
 rearleaf bodies
 
std::shared_ptr< ChLinkLockSphericalm_rearleafSph [2]
 rearleaf-chassis spherical joint
 
std::shared_ptr< ChVehicleJointm_rearleafRev [2]
 rearleaf-clampB rotational joint
 
std::shared_ptr< ChBodym_clampA [2]
 clampA bodies
 
std::shared_ptr< ChVehicleJointm_clampARev [2]
 clampA-axleTube rotational joint Z
 
std::shared_ptr< ChBodym_clampB [2]
 clampB bodies
 
std::shared_ptr< ChVehicleJointm_clampBRev [2]
 clampB-axleTube rotational joint Z
 
std::shared_ptr< ChLinkRSDAm_latRotSpringA [2]
 mimics lateral stiffness of frontleaf
 
std::shared_ptr< ChLinkRSDAm_latRotSpringB [2]
 mimics lateral stiffness of rearleaf
 
std::shared_ptr< ChLinkRSDAm_vertRotSpringA [2]
 mimics vertical stiffness of frontleaf
 
std::shared_ptr< ChLinkRSDAm_vertRotSpringB [2]
 mimics vertical stiffness of rearleaf
 
- Protected Attributes inherited from chrono::vehicle::ChSuspension
ChVector m_rel_loc
 location relative to chassis
 
std::shared_ptr< ChBodym_spindle [2]
 handles to spindle bodies
 
std::shared_ptr< ChShaftm_axle [2]
 handles to axle shafts
 
std::shared_ptr< ChShaftsBodym_axle_to_spindle [2]
 handles to spindle-shaft connectors
 
std::shared_ptr< ChLinkLockRevolutem_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
 
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
 

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< ChLinkRSDA >> 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.
 
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).
 

Member Enumeration Documentation

◆ PointId

Identifiers for the various hardpoints.

Enumerator
SHOCK_A 

shock, axle

SHOCK_C 

shock, chassis

SPRING_A 

spring, axle

SPRING_C 

spring, chassis

SPINDLE 

spindle location

CLAMP_A 

foremost point of the clamped part of the leafspring on the axle tube

CLAMP_B 

rearmost point of the clamped part of the leafspring on the axle tube

FRONT_HANGER 

connection point of the front leaf / shackle to the chassis

REAR_HANGER 

connection point of the rear leaf / shackle to the chassis

SHACKLE 

connection point of the shackle and the front/rear leaf

Constructor & Destructor Documentation

◆ ChSAELeafspringAxle()

chrono::vehicle::ChSAELeafspringAxle::ChSAELeafspringAxle ( const std::string &  name)
Parameters
[in]namename of the subsystem

Member Function Documentation

◆ AddVisualizationAssets()

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

Add visualization assets for the suspension subsystem.

This default implementation uses primitives.

Reimplemented from chrono::vehicle::ChSuspension.

◆ getClampBushingData()

virtual std::shared_ptr<ChVehicleBushingData> chrono::vehicle::ChSAELeafspringAxle::getClampBushingData ( ) const
inlineprotectedvirtual

Return stiffness and damping data for the clamp bushing.

Returning nullptr (default) results in using a kinematic revolute joint.

Reimplemented in chrono::vehicle::SAELeafspringAxle.

◆ getLeafspringBushingData()

virtual std::shared_ptr<ChVehicleBushingData> chrono::vehicle::ChSAELeafspringAxle::getLeafspringBushingData ( ) const
inlineprotectedvirtual

Return stiffness and damping data for the leafspring bushing.

Returning nullptr (default) results in using a kinematic revolute joint.

Reimplemented in chrono::vehicle::SAELeafspringAxle.

◆ getLocation()

virtual const ChVector chrono::vehicle::ChSAELeafspringAxle::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::uaz::UAZBUS_SAELeafspringAxle.

◆ getShackleBushingData()

virtual std::shared_ptr<ChVehicleBushingData> chrono::vehicle::ChSAELeafspringAxle::getShackleBushingData ( ) const
inlineprotectedvirtual

Return stiffness and damping data for the shackle bushing.

Returning nullptr (default) results in using a kinematic revolute joint.

Reimplemented in chrono::vehicle::SAELeafspringAxle.

◆ Initialize()

void chrono::vehicle::ChSAELeafspringAxle::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. Since this suspension is non-steerable, the steering subsystem is always ignored.

Parameters
[in]chassisassociated chassis subsystem
[in]subchassisassociated subchassis subsystem (may be null)
[in]steeringassociated steering subsystem (may be null)
[in]locationlocation relative to the chassis frame
[in]left_ang_velinitial angular velocity of left wheel
[in]right_ang_velinitial angular velocity of right wheel

Implements chrono::vehicle::ChSuspension.

◆ InitializeInertiaProperties()

void chrono::vehicle::ChSAELeafspringAxle::InitializeInertiaProperties ( )
overrideprotectedvirtual

Initialize subsystem inertia properties.

Derived classes must override this function and set the subsystem mass (m_mass) and, if constant, the subsystem COM frame and its inertia tensor. This function is called during initialization of the vehicle system.

Implements chrono::vehicle::ChPart.

◆ UpdateInertiaProperties()

void chrono::vehicle::ChSAELeafspringAxle::UpdateInertiaProperties ( )
overrideprotectedvirtual

Update subsystem inertia properties.

Derived classes must override this function and set the global subsystem transform (m_xform) and, unless constant, the subsystem COM frame (m_com) and its inertia tensor (m_inertia). Calculate the current inertia properties and global frame of this subsystem. This function is called every time the state of the vehicle system is advanced in time.

Implements chrono::vehicle::ChPart.


The documentation for this class was generated from the following files:
  • /builds/uwsbel/chrono/src/chrono_vehicle/wheeled_vehicle/suspension/ChSAELeafspringAxle.h
  • /builds/uwsbel/chrono/src/chrono_vehicle/wheeled_vehicle/suspension/ChSAELeafspringAxle.cpp