Template Class Navigator

Class Documentation

template<class ActionT>
class Navigator

Navigator interface that acts as a base class for all BT-based Navigator action’s plugins.

Public Types

using Ptr = std::shared_ptr<nav2_bt_navigator::Navigator<ActionT>>

Public Functions

inline Navigator()

A Navigator constructor.

virtual ~Navigator() = default

Virtual destructor.

inline bool on_configure(rclcpp_lifecycle::LifecycleNode::WeakPtr parent_node, const std::vector<std::string> &plugin_lib_names, const FeedbackUtils &feedback_utils, nav2_bt_navigator::NavigatorMuxer *plugin_muxer, std::shared_ptr<nav2_util::OdomSmoother> odom_smoother)

Configuration to setup the navigator’s backend BT and actions.

Parameters:

  • parent_node – The ROS parent node to utilize

  • plugin_lib_names – a vector of plugin shared libraries to load

  • feedback_utils – Some utilities useful for navigators to have

  • plugin_muxer – The muxing object to ensure only one navigator can be active at a time

  • odom_smoother – Object to get current smoothed robot’s speed

Returns:

bool If successful

inline bool on_activate()

Activation of the navigator’s backend BT and actions.

Returns:

bool If successful

inline bool on_deactivate()

Deactivation of the navigator’s backend BT and actions.

Returns:

bool If successful

inline bool on_cleanup()

Cleanup a navigator.

Returns:

bool If successful

virtual std::string getName() = 0

Get the action name of this navigator to expose.

Returns:

string Name of action to expose

virtual std::string getDefaultBTFilepath(rclcpp_lifecycle::LifecycleNode::WeakPtr node) = 0
inline std::unique_ptr<nav2_behavior_tree::BtActionServer<ActionT>> &getActionServer()

Get the action server.

Returns:

Action server pointer

Protected Functions

inline bool onGoalReceived(typename ActionT::Goal::ConstSharedPtr goal)

An intermediate goal reception function to mux navigators.

inline void onCompletion(typename ActionT::Result::SharedPtr result, const nav2_behavior_tree::BtStatus final_bt_status)

An intermediate completion function to mux navigators.

virtual bool goalReceived(typename ActionT::Goal::ConstSharedPtr goal) = 0

A callback to be called when a new goal is received by the BT action server Can be used to check if goal is valid and put values on the blackboard which depend on the received goal.

virtual void onLoop() = 0

A callback that defines execution that happens on one iteration through the BT Can be used to publish action feedback.

virtual void onPreempt(typename ActionT::Goal::ConstSharedPtr goal) = 0

A callback that is called when a preempt is requested.

virtual void goalCompleted(typename ActionT::Result::SharedPtr result, const nav2_behavior_tree::BtStatus final_bt_status) = 0

A callback that is called when a the action is completed; Can fill in action result message or indicate that this action is done.

inline virtual bool configure(rclcpp_lifecycle::LifecycleNode::WeakPtr, std::shared_ptr<nav2_util::OdomSmoother>)
Parameters:

Method – to configure resources.

inline virtual bool cleanup()

Method to cleanup resources.

inline virtual bool activate()

Method to activate any threads involved in execution.

inline virtual bool deactivate()

Method to deactivate and any threads involved in execution.

Protected Attributes

std::unique_ptr<nav2_behavior_tree::BtActionServer<ActionT>> bt_action_server_
rclcpp::Logger logger_ = {rclcpp::get_logger("Navigator")}
rclcpp::Clock::SharedPtr clock_
FeedbackUtils feedback_utils_
NavigatorMuxer *plugin_muxer_