A simple joint position controller, which controls each joint independently of each other using a PD control scheme. More...

#include <joint_position_controller.h>

Public Member Functions
bool	init (pr2_mechanism_model::RobotState *robot_state, ros::NodeHandle &nh)
	Initialises the controller and loads all necessary parameters.
void	starting ()
	Starts the controller in real-time and resets the used data structures.
void	stopping ()
void	update ()
	Update loop of the controller (in real-time)
Private Member Functions
void	jointStatesCmdCB (const sensor_msgs::JointState::ConstPtr &command)
	callback function for the subscriber, which receives the desired joint positions
Private Attributes
double	dt_
KDL::JntArray	Kd_
KDL::JntArray	Kp_
ros::Time	last_time_
bool	limit_error_
unsigned int	loop_count_
unsigned int	nrOfJnts_
KDL::JntArray	q_
KDL::JntArray	q_desi_
KDL::JntArray	q_err_
KDL::JntArray	q_err_dot_
double	q_err_dot_max_
double	q_err_max_
KDL::JntArray	q_err_old_
pr2_mechanism_model::RobotState *	robot_state_
ros::Subscriber	sub_joint_states_cmd
KDL::JntArray	tau_
KDL::JntArray	tau_max_
pr2_mechanism_model::Tree	tree_

Detailed Description

A simple joint position controller, which controls each joint independently of each other using a PD control scheme.

Author:: Marcus Liebhardt This joint position controller tries to minimise the position error of all joints in the given KDL::Tree. In doing so, all joints are controlled independently. It also limits the calculated efforts as well as joint position errors. The desired joint positions are received from a topic.

Definition at line 53 of file joint_position_controller.h.

Member Function Documentation

bool JointPositionController::init	(	pr2_mechanism_model::RobotState *	robot_state,
		ros::NodeHandle &	nh
	)

Initialises the controller and loads all necessary parameters.

Initialises the controller and loads all necessary parameters

Parameters:

robot_state	pointer to the robot state
nh	node handle

Returns:: always true

Pick the gains

Definition at line 62 of file joint_position_controller.cpp.

void JointPositionController::jointStatesCmdCB ( const sensor_msgs::JointState::ConstPtr & command ) [private]

callback function for the subscriber, which receives the desired joint positions

Parameters:

command pointer to sensor_msgs::JointState message containing the new desired joint positions

Definition at line 46 of file joint_position_controller.cpp.

void JointPositionController::starting ( )

Starts the controller in real-time and resets the used data structures.

Starts the controller in real time and resets the used data structures; the initialisation of the controller runs in non-real-time.

Definition at line 148 of file joint_position_controller.cpp.

void JointPositionController::stopping ( )

Stops the controller (in real-time)

Definition at line 261 of file joint_position_controller.cpp.

void JointPositionController::update ( )

Update loop of the controller (in real-time)

The update loop determines the current position error of each joints and calculates the joint efforts to minimise the position error. Joint position error and effort limiting is also done here. The update loop also runs in real-time.

Definition at line 162 of file joint_position_controller.cpp.