Waypoint Follower

Source code on Github.

The Waypoint Follower module implements a way of doing waypoint following using the NavigateToPose action server. It will take in a set of ordered waypoints to follow and then try to navigate to them in order. It also hosts a waypoint task executor plugin which can be used to perform custom behavior at a waypoint like waiting for user instruction, taking a picture, or picking up a box. If a waypoint is not achievable, the stop_on_failure parameter will determine whether to continue to the next point or stop.

Parameters

stop_on_failure

Type	Default
bool	true

Description: Whether to fail action task if a single waypoint fails. If false, will continue to next waypoint.

loop_rate

Type	Default
int	20

Description: Rate to check for results from current navigation task.

global_frame_id

Type	Default
string	‘map’

Description: The name of the global coordinate frame published by robot_localization. Only used by the gps_waypoint_follower to convert GPS waypoints to this frame.

service_introspection_mode

Type	Default
string	“disabled”

Description: The introspection mode for services. Options are “disabled”, “metadata”, “contents”.

action_server_result_timeout

Type	Default	Unit
double	900.0	seconds

Description: The timeout value (in seconds) for action servers to discard a goal handle if a result has not been produced. This used to default to 15 minutes in rcl but was changed to 10 seconds in this PR #1012, which may be less than some actions in Nav2 take to run. For most applications, this should not need to be adjusted as long as the actions within the server do not exceed this deadline. This issue has been raised with OSRF to find another solution to avoid active goal timeouts for bookkeeping, so this is a semi-temporary workaround

bond_heartbeat_period

Type	Default
double	0.1

Description: The lifecycle node bond mechanism publishing period (on the /bond topic). Disabled if inferior or equal to 0.0.

waypoint_task_executor_plugin

Type	Default
string	‘wait_at_waypoint’

Description

A plugin to define tasks to be executed when robot arrives to a waypoint.

Note

The plugin namespace defined needs to have a plugin parameter defining the type of plugin to be loaded in the namespace.

Example:

waypoint_follower:
  ros__parameters:
    waypoint_task_executor_plugin: "wait_at_waypoint"
    wait_at_waypoint:
      plugin: "nav2_waypoint_follower::WaitAtWaypoint"
      enabled: True
      waypoint_pause_duration: 0

Provided Plugins

The plugins listed below are inside the nav2_waypoint_follower namespace.

Default Plugin

Namespace

Plugin

“wait_at_waypoint”

“nav2_waypoint_follower::WaitAtWaypoint”

Example

waypoint_follower:
  ros__parameters:
    loop_rate: 20
    stop_on_failure: false
    waypoint_task_executor_plugin: "wait_at_waypoint"
    service_introspection_mode: "disabled"
      wait_at_waypoint:
        plugin: "nav2_waypoint_follower::WaitAtWaypoint"
        enabled: True
        waypoint_pause_duration: 0