##

VariableGearboxPlugin Class Reference

A plugin that uses piecewise cubic Hermite splines to support arbitrary smooth input-output relationships between the input and output angles of a gearbox. More...

`#include <VariableGearboxPlugin.hh>`

Inherits ModelPlugin.

## Public Types

typedef boost::shared_ptr< ModelPlugin > | TPtr
| plugin pointer type definition More...

## Public Member Functions

| VariableGearboxPlugin ()
| Constructor. More...
virtual | ~VariableGearboxPlugin ()
| Destructor. More...
std::string | GetFilename () const
| Get the name of the handler. More...
std::string | GetHandle () const
| Get the short name of the handler. More...
PluginType | GetType () const
| Returns the type of the plugin. More...
virtual void | Init ()
| Override this method for custom plugin initialization behavior. More...
void | Load (physics::ModelPtr _parent, sdf::ElementPtr _sdf)
| Load the controller. More...
virtual void | Reset ()
| Override this method for custom plugin reset behavior. More...

## Static Public Member Functions

static TPtr | Create (const std::string &_filename, const std::string &_name)
| a class method that creates a plugin from a file name. More...

## Protected Member Functions

void | LoadParam (const sdf::ElementPtr &_sdf, const std::string &_name, V &_target, V _defaultValue=V()) const
| Load parameter value from _sdf and store it to the given reference, using the supplied default value if the element in _sdf is not found. More...
void | LoadParam (sdf::ElementPtr &_sdf, const std::string &_name, std::string &_target, const char *_defaultValue) const
| Load parameter value from _sdf and store it to the given reference, using the supplied default value if the element in _sdf is not found. More...

## Protected Attributes

std::string | filename
| Path to the shared library file. More...
std::string | handleName
| Short name. More...
PluginType | type
| Type of plugin. More...

## Detailed Description

A plugin that uses piecewise cubic Hermite splines to support arbitrary smooth input-output relationships between the input and output angles of a gearbox.

It currently works for the ODE gearbox joint.

The ODE gearbox joint now supports linear constriants of the form:

        angle1 - refAngle1 = -ratio * (angle2 - refAngle2)

At each timestep, this plugin linearizes the splines based on the current joint state to compute refAngle1, refAngle2, and ratio and sets them in the ODE gearbox joint. The ODE solver then solves a linearized form of the nonlinear variable gearbox constraint.

The plugin parameters are the gearbox_joint_name as a string and multiple x_y_dydx parameters for specifying points and slopes of the input-output curves that will be interpolated by splines:

x: angle of the input joint y: angle of the output joint dy/dx: instantaneous gear ratio (change in output) / (change in input)

The following example snippet is taken from variable_gearbox_plugin.world

      <plugin name="variable_gearbox" filename="libVariableGearboxPlugin.so">
        <gearbox_joint_name>demo_joint_types::gearbox_demo</gearbox_joint_name>
        <x_y_dydx>1.2  -1.2  -1.0</x_y_dydx>
        <x_y_dydx>1.8  -7.5 -20.0</x_y_dydx>
      </plugin>

To aid in visualizing the splines produced by this plugin, please see the following ipython notebook: https://gist.github.com/scpeters/f7d87dd6578dee3fb95b90b402046679

## Member Typedef Documentation

## TPtr

typedef boost::shared_ptr<ModelPlugin > TPtr

inherited

plugin pointer type definition

## Constructor & Destructor Documentation

## VariableGearboxPlugin()

VariableGearboxPlugin | ( |  | ) |

Constructor.

## ~VariableGearboxPlugin()

virtual ~VariableGearboxPlugin | ( |  | ) |

virtual

Destructor.

## Member Function Documentation

## Create()

static TPtr Create | ( | const std::string & | _filename,
|  | const std::string & | _name
| ) |  |

inline static inherited

a class method that creates a plugin from a file name.

It locates the shared library and loads it dynamically.

Parameters

  [in] | _filename | the path to the shared library.
  [in] | _name | short name of the plugin

Returns
  Shared Pointer to this class type

## GetFilename()

std::string GetFilename | ( |  | ) | const

inline inherited

Get the name of the handler.

## GetHandle()

std::string GetHandle | ( |  | ) | const

inline inherited

Get the short name of the handler.

## GetType()

PluginType GetType | ( |  | ) | const

inline inherited

Returns the type of the plugin.

Returns
  type of the plugin

## Init()

virtual void Init | ( |  | ) |

inline virtual inherited

Override this method for custom plugin initialization behavior.

Reimplemented in TrackedVehiclePlugin, KeysToCmdVelPlugin, SimpleTrackedVehiclePlugin, WheelTrackedVehiclePlugin, BuoyancyPlugin, HarnessPlugin, FollowerPlugin, PlaneDemoPlugin, MudPlugin, CartDemoPlugin, VehiclePlugin, GimbalSmall2dPlugin, LinearBatteryPlugin, DiffDrivePlugin, and SphereAtlasDemoPlugin.

## Load()

void Load | ( | physics::ModelPtr | _parent,
|  | sdf::ElementPtr | _sdf
| ) |  |

virtual

Load the controller.

Implements ModelPlugin.

## LoadParam() [1/2]

void LoadParam | ( | const sdf::ElementPtr & | _sdf,
|  | const std::string & | _name,
|  | V & | _target,
|  | V | _defaultValue = `V()`
| ) |  | const

inline protected inherited

Load parameter value from _sdf and store it to the given reference, using the supplied default value if the element in _sdf is not found.

A message is written using gzmsg reporting whether the default value was used or not.

Parameters

  [in] | _sdf | The SDF element of the plugin.
  [in] | _name | Name of a tag inside the SDF.
  [out] | _target | The reference to store the param value to.
  [in] | _defaultValue | The default value.

## LoadParam() [2/2]

void LoadParam | ( | sdf::ElementPtr & | _sdf,
|  | const std::string & | _name,
|  | std::string & | _target,
|  | const char * | _defaultValue
| ) |  | const

inline protected inherited

Load parameter value from _sdf and store it to the given reference, using the supplied default value if the element in _sdf is not found.

A message is written using gzmsg reporting whether the default value was used or not. String specialization to allow accepting const char* values for std::string parameters.

Parameters

  [in] | _sdf | The SDF element of the plugin.
  [in] | _name | Name of a tag inside the SDF.
  [out] | _target | The reference to store the param value to.
  [in] | _defaultValue | The default value.

## Reset()

virtual void Reset | ( |  | ) |

inline virtual inherited

Override this method for custom plugin reset behavior.

Reimplemented in TrackedVehiclePlugin, KeysToCmdVelPlugin, SimpleTrackedVehiclePlugin, WheelTrackedVehiclePlugin, RandomVelocityPlugin, ElevatorPlugin, FollowerPlugin, LinearBatteryPlugin, ActorPlugin, InitialVelocityPlugin, and SphereAtlasDemoPlugin.

## Member Data Documentation

## filename

std::string filename

protected inherited

Path to the shared library file.

## handleName

std::string handleName

protected inherited

Short name.

## type

PluginType type

protected inherited

Type of plugin.

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

- VariableGearboxPlugin.hh