Description

Base class for a ROS handler.

A specific handler should inherit from here. A handler is essentially a wrapper around a ROS subscriber/publisher/service/action.

IMPORTANT: To support IPC communication while avoiding VSG symbol collisions, handlers should be split into two logical parts:

Data extraction from Chrono (runs in main process, NO ROS symbols)
ROS publishing/subscribing (runs in subprocess or direct mode, full ROS API)

This split is transparent to the handler implementation - the framework automatically handles serialization and IPC when needed. Handlers define a data struct and implement methods to extract/apply data and publish/subscribe.

#include <ChROSHandler.h>

Inheritance diagram for chrono::ros::ChROSHandler:

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Public Types
typedef chrono::ros::ipc::MessageType	MessageType
	Get the message type of this handler. More...

Public Member Functions
virtual	~ChROSHandler ()=default
	Destructor for the ChROSHandler.

virtual bool	Initialize (std::shared_ptr< ChROSInterface > interface)=0
	Initializes the handler. More...

const double	GetUpdateRate () const
	Get the period which this handler operates at.

const uint64_t	GetTickCount () const
	Get the number of times Tick() has been called.

virtual bool	IsPublisher () const
	Check if this handler is a publisher (data flows from Chrono to ROS) Default is true. More...

virtual chrono::ros::ipc::MessageType	GetMessageType () const

virtual std::vector< uint8_t >	GetSerializedData (double time)
	Get serialized data from this handler for IPC transmission. More...

virtual void	PublishFromSerialized (const std::vector< uint8_t > &data, std::shared_ptr< ChROSInterface > interface)
	Publish data to ROS from serialized bytes. More...

virtual void	ApplyFromSerialized (const std::vector< uint8_t > &data)
	Apply data to Chrono from serialized bytes. More...

virtual void	SubscribeAndForward (std::shared_ptr< ChROSInterface > interface, std::function< void(const std::vector< uint8_t > &)> callback)
	Setup subscriber in subprocess to send data back to main process. More...

virtual void	HandleIncomingMessage (const ipc::Message &msg)
	Handle incoming IPC message from ROS subscriber (bidirectional communication). More...

virtual bool	SupportsIncomingMessages () const
	Returns true if this handler processes incoming IPC messages. More...

Protected Member Functions
	ChROSHandler (double update_rate)
	Constructor for the ChROSHandler. More...

void	IncrementTickCount ()
	Increment the tick count.

Member Typedef Documentation

◆ MessageType

typedef chrono::ros::ipc::MessageType chrono::ros::ChROSHandler::MessageType

Get the message type of this handler.

Must be implemented by derived classes to identify the IPC message type.

Returns: The IPC message type for this handler

Constructor & Destructor Documentation

◆ ChROSHandler()

chrono::ros::ChROSHandler::ChROSHandler ( double update_rate )

explicitprotected

Constructor for the ChROSHandler.

Parameters

update_rate Update rate with which the handler should tick relative to the simulation clock. NOTE: A update_rate of 0 indicates tick should be called on each update of the simulation.

Member Function Documentation

◆ ApplyFromSerialized()

virtual void chrono::ros::ChROSHandler::ApplyFromSerialized ( const std::vector< uint8_t > & data )

inlinevirtual

Apply data to Chrono from serialized bytes.

Framework calls this in main process for subscribers. Handler should deserialize and apply to Chrono objects. Default implementation does nothing for backward compatibility.

Parameters

data	Serialized data bytes

◆ GetSerializedData()

virtual std::vector<uint8_t> chrono::ros::ChROSHandler::GetSerializedData ( double time )

inlinevirtual

Get serialized data from this handler for IPC transmission.

Framework calls this in main process for publishers. Handler should extract Chrono data and return as byte vector. Default implementation calls Tick() for backward compatibility.

Parameters

time	Current simulation time

Returns: Serialized data as byte vector (empty if not supported)

Reimplemented in chrono::ros::ChROSDriverInputsHandler, chrono::ros::ChROSClockHandler, chrono::ros::ChROSCameraHandler, chrono::ros::ChROSTFHandler, chrono::ros::ChROSLidarHandler, chrono::ros::ChROSBodyHandler, chrono::ros::ChROSViperDCMotorControlHandler, chrono::ros::ChROSRobotModelHandler, chrono::ros::ChROSAccelerometerHandler, chrono::ros::ChROSGyroscopeHandler, chrono::ros::ChROSMagnetometerHandler, and chrono::ros::ChROSGPSHandler.

◆ HandleIncomingMessage()

virtual void chrono::ros::ChROSHandler::HandleIncomingMessage ( const ipc::Message & msg )

inlinevirtual

Handle incoming IPC message from ROS subscriber (bidirectional communication).

Override this in handlers that receive data from ROS via IPC. Base implementation does nothing - only bidirectional subscribers override this.

Parameters

msg	The incoming IPC message to process

Reimplemented in chrono::ros::ChROSDriverInputsHandler, and chrono::ros::ChROSViperDCMotorControlHandler.

◆ Initialize()

virtual bool chrono::ros::ChROSHandler::Initialize ( std::shared_ptr< ChROSInterface > interface )

pure virtual

Initializes the handler.

Must be implemented by derived classes. This is called after rclcpp::init(). In IPC mode, this is only called in the subprocess. In direct mode, called in main process. Here the underlying ROS objects (e.g. publisher, subscription) should be created.

Parameters

interface The interface to the ROS node

Implemented in chrono::ros::ChROSDriverInputsHandler, chrono::ros::ChROSClockHandler, chrono::ros::ChROSCameraHandler, chrono::ros::ChROSLidarHandler, chrono::ros::ChROSTFHandler, chrono::ros::ChROSBodyHandler, chrono::ros::ChROSRobotModelHandler, chrono::ros::ChROSAccelerometerHandler, chrono::ros::ChROSGyroscopeHandler, chrono::ros::ChROSMagnetometerHandler, chrono::ros::ChROSViperDCMotorControlHandler, and chrono::ros::ChROSGPSHandler.

◆ IsPublisher()

virtual bool chrono::ros::ChROSHandler::IsPublisher ( ) const

inlinevirtual

Check if this handler is a publisher (data flows from Chrono to ROS) Default is true.

Override to false for subscribers.

◆ PublishFromSerialized()

virtual void chrono::ros::ChROSHandler::PublishFromSerialized	(	const std::vector< uint8_t > &	data,
		std::shared_ptr< ChROSInterface >	interface
	)

inlinevirtual

Publish data to ROS from serialized bytes.

Framework calls this in subprocess (or direct mode) for publishers. Handler should deserialize and publish to ROS topics. Default implementation does nothing for backward compatibility.

Parameters

data	Serialized data bytes
interface	ROS interface to use for publishing

Reimplemented in chrono::ros::ChROSBodyHandler.

◆ SubscribeAndForward()

virtual void chrono::ros::ChROSHandler::SubscribeAndForward	(	std::shared_ptr< ChROSInterface >	interface,
		std::function< void(const std::vector< uint8_t > &
	)

inlinevirtual

Setup subscriber in subprocess to send data back to main process.

Framework calls this in subprocess for subscribers. Handler should create ROS subscription and call callback with serialized data. Default implementation does nothing for backward compatibility.

Parameters

interface	ROS interface to use for subscribing
callback	Function to call with serialized data when ROS message arrives

◆ SupportsIncomingMessages()

virtual bool chrono::ros::ChROSHandler::SupportsIncomingMessages ( ) const

inlinevirtual

Returns true if this handler processes incoming IPC messages.

Override to return true in bidirectional subscriber handlers.

Reimplemented in chrono::ros::ChROSDriverInputsHandler, and chrono::ros::ChROSViperDCMotorControlHandler.

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

/builds/uwsbel/chrono/src/chrono_ros/ChROSHandler.h
/builds/uwsbel/chrono/src/chrono_ros/ChROSHandler.cpp

Description

Public Types

Public Member Functions

Protected Member Functions

Member Typedef Documentation

◆ MessageType

Constructor & Destructor Documentation

◆ ChROSHandler()

Member Function Documentation

◆ ApplyFromSerialized()

◆ GetSerializedData()

◆ HandleIncomingMessage()

◆ Initialize()

◆ IsPublisher()

◆ PublishFromSerialized()

◆ SubscribeAndForward()

◆ SupportsIncomingMessages()