panda_gazebo.core

Contains the core components (classes and functions) that are needed for creating the panda_gazebo simulation.

Submodules

• panda_gazebo.core.control_server
• panda_gazebo.core.control_switcher
• panda_gazebo.core.moveit_server

Package Contents

Classes

PandaControlServer	Controller server used to send control commands to the simulated Panda Robot.
PandaControlSwitcher	Used for switching the Panda robot controllers.
PandaMoveItPlannerServer	Used to control or request information from the Panda Robot. This is done using

class panda_gazebo.core.PandaControlServer(autofill_traj_positions=False, load_gripper=True, load_set_joint_commands_service=True, load_arm_follow_joint_trajectory_action=False, load_extra_services=False, controllers_check_rate=CONTROLLER_INFO_RATE)

Bases: object

Controller server used to send control commands to the simulated Panda Robot.

joint_states

The current joint states.

Type:

sensor_msgs.JointState

arm_joint_positions_threshold

The current threshold for determining whether the arm joint positions are within the given setpoint.

Type:

float

arm_joint_efforts_threshold

The current threshold for determining whether the arm joint efforts are within the given setpoint.

Type:

float

arm_velocity_threshold

The current threshold for determining whether the arm has zero velocity.

Type:

float

Initialise PandaControlServer object.

Parameters:

• autofill_traj_positions (bool, optional) – Whether you want to automatically set the current states as positions when the positions field of the joint trajectory message is left empty. Defaults to False.

• load_gripper (boolean, optional) – Whether we also want to load the gripper control services.

• load_set_joint_commands_service (boolean, optional) – Whether the set joint commands service should be loaded. This service is used by the ros_gazebo_gym package when the control type is NOT set to trajectory. Defaults, to True.

• load_arm_follow_joint_trajectory_action (boolean, optional) – Whether the arm follow joint trajectory action should be loaded. This service is used by the ros_gazebo_gym package when the control type is set to trajectory. Defaults, to False.

• load_extra_services (bool, optional) – Whether to load extra services that are not used by the ros_gazebo_gym package. Defaults to False.

• controllers_check_rate (float, optional) – Rate at which the availability of the used controllers is checked. Setting this to -1 will check at every time step. Defaults to 0.1 Hz.

Warning

Please note that increasing the controllers_check_rate decreases the control frequency.

property arm_trajectory_action_preempted

Returns whether the arm joint trajectory action server is preempted.

property controlled_joints

Returns the joints that can be controlled by a each control type.

Important

This does not mean that the necessary controller is running. It only means that the controller was loaded and can be used to control the joints when it is started.

Returns:

A dictionary containing the joints that are controlled when using a

given control type (i.e. control_type>``control_group``>``controller``).

Return type:

dict

property joint_controllers

Retrieves the controllers which are currently loaded to control each joint.

Returns:

A dictionary where the keys are joint names and the values are

lists of controllers that can control the joint.

Return type:

dict

property controllers

Retrieves info about the loaded controllers.

Note

This method is cached to reduce the number of calls to the controller manager and therefore increase performance.

Returns:

Dictionary with information about the currently loaded controllers.

Return type:

dict

property gripper_width

Returns the gripper width as calculated based on the Panda finger joints.

Returns:

The gripper width.

Return type:

float

class panda_gazebo.core.PandaControlSwitcher(connection_timeout=10, verbose=True, robot_name_space='')

Bases: object

Used for switching the Panda robot controllers.

verbose

Boolean specifying whether we want to display log messages during switching.

Type:

bool

arm_control_types

List of currently active arm control types.

Type:

list

hand_control_types

List of currently active hand control types.

Type:

list

Initialise PandaControlSwitcher object.

Parameters:

• connection_timeout (str, optional) – The timeout for connecting to the controller_manager services. Defaults to 10 sec.

• verbose (bool, optional) – Whether to display debug log messages. Defaults to True.

• robot_name_space (string, optional) – The namespace the robot, and thus the ‘controller_manager’ is on. Defaults to "".

property arm_control_types

Returns the currently active arm control types. Returns empty list when no control type is enabled.

property hand_control_types

Returns the currently active hand control types. Returns empty when no control type is enabled.

wait_for_control_type(control_group, control_type, timeout=None, rate=10)

Function that can be used to wait till all the controllers used for a given ‘control_group’ and ‘control_type’ are running. Useful four when you expect a launch file to load certain controllers.

Parameters:

• control_group (str) – The control group of which you want the switch the control type. Options are hand or arm.

• control_type (str) – The robot control type you want to switch to for the given ‘control_group’. Options are: trajectory, position and effort.

• timeout (float, optional) – The function timeout. Defaults to None meaning the function will wait for ever.

• rate (int, optional) – The ‘control_type’ check rate. Defaults to 10 hz.

Raises:

TimeoutError – Thrown when the set timeout has passed.

switch(control_group, control_type, load_controllers=True, timeout=3, verbose=None)

Switch Panda robot control type. This function stops all currently running controllers and starts the required controllers for a given control type.

Parameters:

• control_group (str) – The control group of which you want the switch the control type. Options are hand or arm.

• control_type (str) – The robot control type you want to switch to for the given ‘control_group’. Options are: trajectory, position and effort.

• load_controllers (bool) – Try to load the required controllers for a given control_type if they are not yet loaded.

• timeout (int, optional) – The timeout for switching to a given controller. Defaults to 3 sec.

• verbose (bool, optional) – Whether to display debug log messages. Defaults to verbose value set during the class initiation.

Returns:

Contains information about whether the switch operation was successful ‘success’ and the previously used controller ‘prev_control_type’.

Return type:

ControllerSwitcherResponse

class panda_gazebo.core.PandaMoveItPlannerServer(arm_move_group='panda_arm', arm_ee_link='panda_link8', hand_move_group='panda_hand', load_gripper=True, load_set_ee_pose_service=True, load_extra_services=False)

Bases: object

Used to control or request information from the Panda Robot. This is done using the MoveIt moveit_commander module.

robot

The MoveIt robot commander object.

Type:

moveit_commander.robot.RobotCommander

scene

The MoveIt robot scene commander object.

Type:

moveit_commander.planning_scene_interface.PlanningSceneInterface

move_group_arm

The MoveIt arm move group object.

Type:

moveit_commander.move_group.MoveGroupCommander

move_group_hand

The MoveIt hand move group object.

Type:

moveit_commander.move_group.MoveGroupCommander

ee_pose_target

The last set ee pose.

Type:

geometry_msgs.msg.Pose

joint_positions_target

Dictionary containing the last Panda arm and hand joint positions setpoint.

Type:

dict

Initialise PandaMoveItPlannerServer object.

Parameters:

• arm_move_group (str, optional) – The name of the move group you want to use for controlling the Panda arm. Defaults to panda_arm.

• arm_ee_link (str, optional) – The end effector you want MoveIt to use when controlling the Panda arm. Defaults to panda_link8.

• hand_move_group (str, optional) – The name of the move group you want to use for controlling the Panda hand. Defaults to panda_hand.

• load_gripper (boolean, optional) – Whether we also want to load the gripper control services. Defaults to True.

• load_set_ee_pose_service (boolean, optional) – Whether the set ee pose service should be loaded. This service is used by the ros_gazebo_gym package when the control type is set to trajectory. Defaults, to True.

• load_extra_services (bool, optional) – Whether to load extra services that are not used by the ros_gazebo_gym package. Defaults to False.