franka::Gripper Class Reference

Maintains a network connection to the gripper, provides the current gripper state, and allows the execution of commands. More...

#include <gripper.h>

Public Types
using	ServerVersion = uint16_t
	Version of the gripper server.

Public Member Functions
	Gripper (const std::string &franka_address)
	Establishes a connection with a gripper connected to a robot.
	Gripper (Gripper &&gripper) noexcept
	Move-constructs a new Gripper instance.
Gripper &	operator= (Gripper &&gripper) noexcept
	Move-assigns this Gripper from another Gripper instance.
	~Gripper () noexcept
	Closes the connection.
bool	homing () const
	Performs homing of the gripper.
bool	grasp (double width, double speed, double force, double epsilon_inner=0.005, double epsilon_outer=0.005) const
	Grasps an object.
bool	move (double width, double speed) const
	Moves the gripper fingers to a specified width.
bool	stop () const
	Stops a currently running gripper move or grasp.
GripperState	readOnce () const
	Waits for a gripper state update and returns it.
ServerVersion	serverVersion () const noexcept
	Returns the software version reported by the connected server.

Detailed Description

Maintains a network connection to the gripper, provides the current gripper state, and allows the execution of commands.

Note

The members of this class are threadsafe.

Examples

grasp_object.cpp.

Constructor & Destructor Documentation

Gripper() [1/2]

franka::Gripper::Gripper ( const std::string &  franka_address )

explicit

Establishes a connection with a gripper connected to a robot.

Parameters

[in]

franka_address

IP/hostname of the robot the gripper is connected to.

Exceptions

NetworkException	if the connection is unsuccessful.
IncompatibleVersionException	if this version of libfranka is not supported.

Gripper() [2/2]

franka::Gripper::Gripper ( Gripper &&  gripper )

noexcept

Move-constructs a new Gripper instance.

Parameters

[in]

gripper

Other Gripper instance.

Member Function Documentation

grasp()

bool franka::Gripper::grasp	(	double	width,
		double	speed,
		double	force,
		double	epsilon_inner = 0.005,
		double	epsilon_outer = 0.005
	)		const

Grasps an object.

An object is considered grasped if the distance \(d\) between the gripper fingers satisfies \((\text{width} - \text{epsilon_inner}) < d < (\text{width} + \text{epsilon_outer})\).

Parameters

[in]	width	Size of the object to grasp in \([m]\).
[in]	speed	Closing speed in \([\frac{m}{s}]\).
[in]	force	Grasping force in \([N]\).
[in]	epsilon_inner	Maximum tolerated deviation when the actual grasped width is smaller than the commanded grasp width.
[in]	epsilon_outer	Maximum tolerated deviation when the actual grasped width is larger than the commanded grasp width.

Returns

True if an object has been grasped, false otherwise.

Exceptions

CommandException	if an error occurred.
NetworkException	if the connection is lost, e.g. after a timeout.

Examples

grasp_object.cpp.

homing()

bool franka::Gripper::homing

(

)

const

Performs homing of the gripper.

After changing the gripper fingers, a homing needs to be done. This is needed to estimate the maximum grasping width.

Returns

True if command was successful, false otherwise.

Exceptions

CommandException	if an error occurred.
NetworkException	if the connection is lost, e.g. after a timeout.

See also

GripperState for the maximum grasping width.

Examples

grasp_object.cpp.

move()

bool franka::Gripper::move	(	double	width,
		double	speed
	)		const

Moves the gripper fingers to a specified width.

Parameters

[in]	width	Intended opening width in \([m]\).
[in]	speed	Closing speed in \([\frac{m}{s}]\).

Returns

True if command was successful, false otherwise.

Exceptions

CommandException	if an error occurred.
NetworkException	if the connection is lost, e.g. after a timeout.

operator=()

Gripper & franka::Gripper::operator= ( Gripper &&  gripper )

noexcept

Move-assigns this Gripper from another Gripper instance.

Parameters

[in]

gripper

Other Gripper instance.

Returns

Model instance.

readOnce()

GripperState franka::Gripper::readOnce

(

)

const

Waits for a gripper state update and returns it.

Returns

Current gripper state.

Exceptions

NetworkException	if the connection is lost, e.g. after a timeout.
InvalidOperationException	if another readOnce is already running.

Examples

grasp_object.cpp.

serverVersion()

ServerVersion franka::Gripper::serverVersion ( ) const

noexcept

Returns the software version reported by the connected server.

Returns

Software version of the connected server.

stop()

bool franka::Gripper::stop

(

)

const

Stops a currently running gripper move or grasp.

Returns

True if command was successful, false otherwise.

Exceptions

CommandException	if an error occurred.
NetworkException	if the connection is lost, e.g. after a timeout.

Examples

grasp_object.cpp.

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

• include/franka/gripper.h