Tracks the latest joint states. More...

#include <joint_state_reader.h>

Public Member Functions
	JointStateReader ()
	Constructor. More...

	JointStateReader (const std::string &joint_states_topic)
	Constructor with a different joint states topic. More...

void	Start ()
	Starts subscribing to the joint states. More...

bool	HasJoint (const std::string &name) const
	Returns true if this reader has a given joint state. More...

double	position (const std::string &name) const
	Returns the position of the given joint. More...

std::map< std::string, double >	positions () const
	Returns all the joint positions so far. More...

bool	WaitForMessages (const ros::Duration &timeout) const
	Wait for at least one JointState message. More...

bool	WaitForJoint (const std::string &name, const ros::Duration &timeout) const
	Wait until a joint value is available. More...

Detailed Description

Tracks the latest joint states.

Currently, we only track joint positions/angles, not velocities or efforts.

Usage:

JointStateReader js_reader;
js_reader.Start();
js_reader.WaitForMessages(ros::Duration(1.0));
if (js_reader.HasJoint("torso_lift_link")) {
  double torso_pos = js_reader.position("torso_lift_link");
}
std::map joint_positions = js_reader.positions();

Definition at line 26 of file joint_state_reader.h.

Constructor & Destructor Documentation

rapid::JointStateReader::JointStateReader ( )

Constructor.

rapid::JointStateReader::JointStateReader ( const std::string & joint_states_topic )

Constructor with a different joint states topic.

Member Function Documentation

bool rapid::JointStateReader::HasJoint ( const std::string & name ) const

Returns true if this reader has a given joint state.

Parameters

[in] name The name of the joint to check.

Returns: true if the reader has received at least one value from the joint_states topic for the given joint, false otherwise.

double rapid::JointStateReader::position ( const std::string & name ) const

Returns the position of the given joint.

Parameters

[in] name The name of the joint.

Exceptions

std::out_of_range if the joint does not exist.

std::map<std::string, double> rapid::JointStateReader::positions ( ) const

Returns all the joint positions so far.

void rapid::JointStateReader::Start ( )

Starts subscribing to the joint states.

The JointStateReader will not work until you call Start().

bool rapid::JointStateReader::WaitForJoint	(	const std::string &	name,
		const ros::Duration &	timeout
	)		const

Wait until a joint value is available.

Blocks until the given joint value has been recorded at least once or the timeout is reached. Usually, calling WaitForMessages will be sufficient, but sometimes different controllers publish different subsets of the robot joint states, and the first message might not contain the joint you are looking for.

Parameters

[in]	name	The name of the joint to wait for.
[in]	timeout	The maximum amount of time to wait.

Returns: true if the joint value was available before the timeout, false otherwise.

bool rapid::JointStateReader::WaitForMessages ( const ros::Duration & timeout ) const

Wait for at least one JointState message.

Blocks until a message is received on the joint_states topic or the timeout is reached. This is useful when you want to read a joint value shortly after calling Start(), and ROS has not had time to process callbacks yet.

Parameters

[in] timeout The maximum amount of time to wait.

Returns: true if a message was received before the timeout, false otherwise.

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

rapid_robot/include/rapid_robot/joint_state_reader.h

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation