Robot Hardware Interface and Resource Manager. More...

#include <robot_hw.h>

Inheritance diagram for hardware_interface::RobotHW:

Public Member Functions
virtual bool	init (ros::NodeHandle &, ros::NodeHandle &)
	The init function is called to initialize the RobotHW from a non-realtime thread. More...

virtual	~RobotHW ()=default

Resource Management
virtual bool	checkForConflict (const std::list< ControllerInfo > &info) const

Control Loop
virtual void	read (const ros::Time &, const ros::Duration &)
	Read data from the robot hardware. More...

virtual void	write (const ros::Time &, const ros::Duration &)
	Write commands to the robot hardware. More...

Public Member Functions inherited from hardware_interface::InterfaceManager
template<class T >
T *	get ()
	Get an interface. More...

std::vector< std::string >	getInterfaceResources (std::string iface_type) const
	Get the resource names registered to an interface, specified by type. More...

std::vector< std::string >	getNames () const
	Lists the demangled names of all registered interfaces. More...

template<class T >
void	registerInterface (T *iface)
	Register an interface. More...

void	registerInterfaceManager (InterfaceManager *iface_man)
	Register another interface manager. More...

Hardware Interface Switching
enum	SwitchState { DONE, ONGOING, ERROR }

virtual bool	prepareSwitch (const std::list< ControllerInfo > &, const std::list< ControllerInfo > &)

virtual void	doSwitch (const std::list< ControllerInfo > &, const std::list< ControllerInfo > &)

virtual SwitchState	switchResult () const
	Return (in realtime) the state of the last doSwitch(). More...

virtual SwitchState	switchResult (const ControllerInfo &) const
	Return (in realtime) the state of the last doSwitch() for a given controller. More...

Additional Inherited Members
Protected Types inherited from hardware_interface::InterfaceManager
typedef std::vector< InterfaceManager * >	InterfaceManagerVector

typedef std::map< std::string, void * >	InterfaceMap

typedef std::map< std::string, std::vector< std::string > >	ResourceMap

typedef std::map< std::string, size_t >	SizeMap

Protected Attributes inherited from hardware_interface::InterfaceManager
std::vector< ResourceManagerBase * >	interface_destruction_list_

InterfaceManagerVector	interface_managers_

InterfaceMap	interfaces_

InterfaceMap	interfaces_combo_

SizeMap	num_ifaces_registered_

ResourceMap	resources_
	This will allow us to check the resources based on the demangled type name of the interface. More...

Detailed Description

Robot Hardware Interface and Resource Manager.

This class provides a standardized interface to a set of robot hardware interfaces to the controller manager. It performs resource conflict checking for a given set of controllers and maintains a map of hardware interfaces. It is meant to be used as a base class for abstracting custom robot hardware.

The hardware interface map (interfaces_) is a 1-to-1 map between the names of interface types derived from HardwareInterface and instances of those interface types.

A class derived from this base interface represents a robot and stores the state of the robot's hardware resources (joints, sensors, actuators) and outgoing commands in its data member arrays. The names of these members should provide semantic meaning (e.g. pos, vel, eff, cmd). Commands from controllers are populated by the controller's update method, (controller_interface::ControllerBase::update()). For each resource a JointStateHandle (for read only joints), JointHandle (for read and write joints) or custom handle can be used which is registered (hardware_interface::ResourceManager::registerHandle) with one of the robot's interface types. Note that JointStateHandle should be preferred in case only reading from the joint is required because it doesn't create conflicts between controllers. For read-only joints it is possible to use JointStateInterface and for joints that accept commands and provide feedback (read and write) JointCommandInterface can be used or one of its derived interfaces (e.g. PositionJointInterface). Another option is to define and use custom ones. The interfaces themselfes are then registered (registerInterface) with the derived robot class. The registration (registerInterface) of interfaces can be done either in the constructor or init of a custom robot hardware class.

Definition at line 78 of file robot_hw.h.

Member Enumeration Documentation

◆ SwitchState

enum hardware_interface::RobotHW::SwitchState

Enumerator
DONE
ONGOING
ERROR

Definition at line 167 of file robot_hw.h.

Constructor & Destructor Documentation

◆ ~RobotHW()

virtual hardware_interface::RobotHW::~RobotHW ( )

virtualdefault

Member Function Documentation

◆ checkForConflict()

virtual bool hardware_interface::RobotHW::checkForConflict ( const std::list< ControllerInfo > & info ) const

inlinevirtual

Check (in non-realtime) if the given set of controllers is allowed to run simultaneously.

This default implementation simply checks if any two controllers use the same resource.

Definition at line 113 of file robot_hw.h.

◆ doSwitch()

virtual void hardware_interface::RobotHW::doSwitch	(	const std::list< ControllerInfo > &	,
		const std::list< ControllerInfo > &
	)

inlinevirtual

Perform (in realtime) all necessary hardware interface switches in order to start and stop the given controllers. Start and stop list are disjoint. The feasability was checked in prepareSwitch() beforehand.

Definition at line 164 of file robot_hw.h.

◆ init()

virtual bool hardware_interface::RobotHW::init	(	ros::NodeHandle &	,
		ros::NodeHandle &
	)

inlinevirtual

The init function is called to initialize the RobotHW from a non-realtime thread.

Initialising a custom robot is done by registering joint handles (hardware_interface::ResourceManager::registerHandle) to hardware interfaces that group similar joints and registering those individual hardware interfaces with the class that represents the custom robot (derived from this hardware_interface::RobotHW)

Note: Registering of joint handles and interfaces can either be done in the constructor or this init method.

Parameters

root_nh	A NodeHandle in the root of the caller namespace.
robot_hw_nh	A NodeHandle in the namespace from which the RobotHW should read its configuration.

Returns: True if initialization was successful

Definition at line 102 of file robot_hw.h.

◆ prepareSwitch()

virtual bool hardware_interface::RobotHW::prepareSwitch	(	const std::list< ControllerInfo > &	,
		const std::list< ControllerInfo > &
	)

inlinevirtual

Check (in non-realtime) if given controllers could be started and stopped from the current state of the RobotHW with regard to necessary hardware interface switches and prepare the switching. Start and stop list are disjoint. This handles the check and preparation, the actual switch is commited in doSwitch().

Definition at line 157 of file robot_hw.h.

◆ read()

virtual void hardware_interface::RobotHW::read	(	const ros::Time &	,
		const ros::Duration &
	)

inlinevirtual

Read data from the robot hardware.

The read method is part of the control loop cycle (read, update, write) and is used to populate the robot state from the robot's hardware resources (joints, sensors, actuators). This method should be called before controller_manager::ControllerManager::update() and write.

Note: The name read refers to reading state from the hardware. This complements write, which refers to writing commands to the hardware.

Querying WallTime inside read is not realtime safe. The parameters time and period make it possible to inject time from a realtime source.

Parameters

time	The current time
period	The time passed since the last call to read

Definition at line 206 of file robot_hw.h.

◆ switchResult() [1/2]

virtual SwitchState hardware_interface::RobotHW::switchResult ( ) const

inlinevirtual

Return (in realtime) the state of the last doSwitch().

Definition at line 175 of file robot_hw.h.

◆ switchResult() [2/2]

virtual SwitchState hardware_interface::RobotHW::switchResult ( const ControllerInfo & ) const

inlinevirtual

Return (in realtime) the state of the last doSwitch() for a given controller.

Definition at line 181 of file robot_hw.h.

◆ write()

virtual void hardware_interface::RobotHW::write	(	const ros::Time &	,
		const ros::Duration &
	)

inlinevirtual

Write commands to the robot hardware.

The write method is part of the control loop cycle (read, update, write) and is used to send out commands to the robot's hardware resources (joints, actuators). This method should be called after read and controller_manager::ControllerManager::update.

Note: The name write refers to writing commands to the hardware. This complements read, which refers to reading state from the hardware.

Querying WallTime inside write is not realtime safe. The parameters time and period make it possible to inject time from a realtime source.

Parameters

time	The current time
period	The time passed since the last call to write

Definition at line 224 of file robot_hw.h.

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

robot_hw.h

Public Member Functions

Hardware Interface Switching

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ SwitchState

Constructor & Destructor Documentation

◆ ~RobotHW()

Member Function Documentation

◆ checkForConflict()

◆ doSwitch()

◆ init()

◆ prepareSwitch()

◆ read()

◆ switchResult() [1/2]

◆ switchResult() [2/2]

◆ write()