configuring-bt-navigator.rst

Behavior-Tree Navigator

Source code on Github.

The BT Navigator (Behavior Tree Navigator) module implements the NavigateToPose task interface. It is a Behavior Tree-based implementation of navigation that is intended to allow for flexibility in the navigation task and provide a way to easily specify complex robot behaviors, including recovery.

Parameters

default_bt_xml_filename:	Type Default string N/A Description Path to the default behavior tree XML description, see :ref:`configuring_behavior_tree_xml` for details on this file.
plugin_lib_names:	Type Default vector<string> ["nav2_compute_path_to_pose_action_bt_node", "nav2_follow_path_action_bt_node", "nav2_back_up_action_bt_node", "nav2_spin_action_bt_node", "nav2_wait_action_bt_node", "nav2_clear_costmap_service_bt_node", "nav2_is_stuck_condition_bt_node", "nav2_goal_reached_condition_bt_node", "nav2_initial_pose_received_condition_bt_node", "nav2_goal_updated_condition_bt_node", "nav2_reinitialize_global_localization_service_bt_node", "nav2_rate_controller_bt_node", "nav2_distance_controller_bt_node", "nav2_speed_controller_bt_node", "nav2_recovery_node_bt_node", "nav2_pipeline_sequence_bt_node", "nav2_round_robin_node_bt_node", "nav2_transform_available_condition_bt_node"] Description List of behavior tree node shared libraries. Consider checking out the :ref:`groot_introduction` tutorial for using this feature.
enable_groot_monitoring:	Type Default bool true Description Enable live Groot monitoring of the current BT status. This is possible due to attaching a ZMQ server and publisher to the active behavior tree. Consider checking out the :ref:`groot_introduction` tutorial for using this feature. Attention: Groot will only work after the behavior tree is running, which means that the nav2 stack has to receive a goal first.
groot_zmq_publisher_port:	Type Default int 1666 Description ZMQ publisher port for the Groot monitor. Used to consecutive publish the current status of the BT as flatbuffer.
groot_zmq_server_port:	Type Default int 1667 Description ZMQ server port for the Groot monitor. Used to send the current bt factory + configuration as flatbuffer on an (empty) request by Groot. Attention: Groot will only work after the behavior tree is running, which means that the nav2 stack has to receive a goal first.
transform_tolerance:	Type Default Unit double 0.1 seconds Description TF transform tolerance.
global_frame:	Type Default string map Description Reference frame.
robot_base_frame:	Type Default string base_link Description Path to behavior tree XML description.
odom_topic:	Type Default string odom Description Topic on which odometry is published
use_sim_time:	Type Default bool false Description Use time provided by simulation.

Example

bt_navigator:
  ros__parameters:
    use_sim_time: true
    global_frame: map
    robot_base_frame: base_link
    transform_tolerance: 0.1
    enable_groot_monitoring: True
    groot_zmq_publisher_port: 1666
    groot_zmq_server_port: 1667
    bt_xml_filename: replace/with/path/to/bt.xml
    plugin_lib_names:
    - nav2_compute_path_to_pose_action_bt_node
    - nav2_follow_path_action_bt_node
    - nav2_back_up_action_bt_node
    - nav2_spin_action_bt_node
    - nav2_wait_action_bt_node
    - nav2_clear_costmap_service_bt_node
    - nav2_is_stuck_condition_bt_node
    - nav2_goal_reached_condition_bt_node
    - nav2_initial_pose_received_condition_bt_node
    - nav2_goal_updated_condition_bt_node
    - nav2_reinitialize_global_localization_service_bt_node
    - nav2_rate_controller_bt_node
    - nav2_distance_controller_bt_node
    - nav2_speed_controller_bt_node
    - nav2_recovery_node_bt_node
    - nav2_pipeline_sequence_bt_node
    - nav2_round_robin_node_bt_node
    - nav2_transform_available_condition_bt_node