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

 ChPitmanArm (const std::string &name)
 
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 void LogConstraintViolations () override
 Log current constraint violations.
 
- Public Member Functions inherited from chrono::vehicle::ChSteering
 ChSteering (const std::string &name)
 
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 track shoe subsystem.
 
void SetName (const std::string &name)
 Set the name identifier for this track shoe 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.
 

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

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 ChVectorgetSteeringLinkInertia () const =0
 Return the moments of inertia of the steering link body.
 
virtual const ChVectorgetPitmanArmInertia () const =0
 Return the moments 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 Attributes

std::shared_ptr< ChBodym_arm
 handle to the Pitman arm body
 
std::shared_ptr< ChLinkEnginem_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< ChLinkUniversalm_universal
 handle to the arm-link universal joint
 
- Protected Attributes inherited from chrono::vehicle::ChSteering
std::shared_ptr< ChBodym_link
 handle to the main steering link
 
- Protected Attributes inherited from chrono::vehicle::ChPart
std::string m_name
 
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
 

Member Enumeration Documentation

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

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

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

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.

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.

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::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.