Description

Base class for a Rack-Pinion 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). The steering link translates along the Y axis. We do not explicitly model the pinion but instead use the implied rack-pinion constraint to calculate the rack displacement from a given pinion rotation angle.

#include <ChRackPinion.h>

Inheritance diagram for chrono::vehicle::ChRackPinion:
Collaboration diagram for chrono::vehicle::ChRackPinion:

Public Member Functions

 ChRackPinion (const std::string &name)
 Construct a rack-pinion steering mechanism with given base name. More...
 
virtual void Initialize (std::shared_ptr< ChBodyAuxRef > chassis, const ChVector<> &location, const ChQuaternion<> &rotation) override
 Initialize the 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 Member Functions

virtual double GetSteeringLinkMass () const =0
 Return the mass of the steering link.
 
virtual ChVector GetSteeringLinkInertia () const =0
 Return the moments of inertia of the steering link.
 
virtual double GetSteeringLinkCOM () const =0
 Return the steering link COM offset in Y direction (positive to the left).
 
virtual double GetSteeringLinkRadius () const =0
 Return the radius of the steering link (visualization only).
 
virtual double GetSteeringLinkLength () const =0
 Return the length of the steering link (visualization only).
 
virtual double GetPinionRadius () const =0
 Return the radius of the pinion.
 
virtual double GetMaxAngle () const =0
 Return the maximum rotation angle of the pinion (in either direction).
 

Protected Attributes

std::shared_ptr
< ChLinkLockPrismatic
m_prismatic
 handle to the prismatic joint chassis-link
 
std::shared_ptr
< ChLinkLinActuator
m_actuator
 handle to the linear actuator on steering link
 
- 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
 

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...
 

Constructor & Destructor Documentation

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

Construct a rack-pinion steering mechanism with given base name.

Parameters
[in]namename of the subsystem

Member Function Documentation

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

Add visualization assets for the steering subsystem.

This default implementation uses primitives.

Reimplemented from chrono::vehicle::ChPart.

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

Initialize the steering subsystem.

This attached the steering mechanism to the specified chassis body at the given offset and orientation, relative to the frame of the chassis.

Parameters
chassispin] handle 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::ChRackPinion::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.