Navigation Plugins

There are a number of plugin interfaces for users to create their own custom applications or algorithms with. Namely, the costmap layer, planner, controller, behavior tree, and behavior plugins. A list of all known plugins are listed here below for ROS 2 Navigation. If you know of a plugin, or you have created a new plugin, please consider submitting a pull request with that information.

This file can be found and editted under sphinx_docs/plugins/index.rst. For tutorials on creating your own plugins, please see Writing a New Costmap2D Plugin, Writing a New Behavior Tree Plugin, Writing a New Controller Plugin, Writing a New Planner Plugin, or writing_new_recovery_plugin.

Costmap Layers

Plugin Name	Creator	Description
Voxel Layer	Eitan Marder-Eppstein	Maintains persistant 3D voxel layer using depth and laser sensor readings and raycasting to clear free space
Range Layer	David Lu	Uses a probabalistic model to put data from sensors that publish range msgs on the costmap
Static Layer	Eitan Marder-Eppstein	Gets static map and loads occupancy information into costmap
Inflation Layer	Eitan Marder-Eppstein	Inflates lethal obstacles in costmap with exponential decay
Obstacle Layer	Eitan Marder-Eppstein	Maintains persistent 2D costmap from 2D laser scans with raycasting to clear free space
Spatio-Temporal Voxel Layer	Steve Macenski	Maintains temporal 3D sparse volumetric voxel grid with decay through sensor models
Non-Persistent Voxel Layer	Steve Macenski	Maintains 3D occupancy grid consisting only of the most sets of measurements

Costmap Filters

Plugin Name	Creator	Description
Keepout Filter	Alexey Merzlyakov	Maintains keep-out/safety zones and preferred lanes for moving
Speed Filter	Alexey Merzlyakov	Limits maximum velocity of robot in speed restriction areas
Binary Filter	Alexey Merzlyakov	Enables binary (boolean) mask behavior to trigger actions.

Controllers

Plugin Name	Creator	Description	Drivetrain support
DWB Controller	David Lu!!	A highly configurable DWA implementation with plugin interfaces	Differential, Omnidirectional, Legged
TEB Controller	Christoph Rösmann	A MPC-like controller suitable for ackermann, differential, and holonomic robots.	Ackermann, Legged, Omnidirectional, Differential
Regulated Pure Pursuit	Steve Macenski	A service / industrial robot variation on the pure pursuit algorithm with adaptive features.	Ackermann, Legged, Differential
Rotation Shim Controller	Steve Macenski	A “shim” controller to rotate to path heading before passing to main controller for tracking.	Differential, Omni, model rotate in place

Planners

Plugin Name	Creator	Description	Drivetrain support
NavFn Planner	Eitan Marder-Eppstein & Kurt Konolige	A navigation function using A* or Dijkstras expansion, assumes 2D holonomic particle	Differential, Omnidirectional, Legged
SmacPlannerHybrid (formerly SmacPlanner)	Steve Macenski	A SE2 Hybrid-A* implementation using either Dubin or Reeds-shepp motion models with smoother and multi-resolution query. Cars, car-like, and ackermann vehicles. Kinematically feasible.	Ackermann, Differential, Omnidirectional, Legged
SmacPlanner2D	Steve Macenski	A 2D A* implementation Using either 4 or 8 connected neighborhoods with smoother and multi-resolution query	Differential, Omnidirectional, Legged
SmacPlannerLattice	Steve Macenski	An implementation of State Lattice Planner using pre-generated minimum control sets for kinematically feasible planning with any type of vehicle imaginable. Includes generator script for Ackermann, diff, omni, and legged robots.	Differential, Omnidirectional, Ackermann, Legged, Arbitrary / Custom
ThetaStarPlanner	Anshumaan Singh	An implementaion of Theta* using either 4 or 8 connected neighborhoods, assumes the robot as a 2D holonomic particle	Differential, Omnidirectional

Smoothers

Plugin Name	Creator	Description
Simple Smoother	Steve Macenski	A simple path smoother for infeasible (e.g. 2D) planners
Constrained Smoother	Matej Vargovcik & Steve Macenski	A path smoother using a constraints problem solver to optimize various criteria such as smoothness or distance from obstacles, maintaining minimum turning radius
Savitzky-Golay Smoother	Steve Macenski	A path smoother using a Savitzky-Golay filter to smooth the path via digital signal processing to remove noise from the path.

Behaviors

Plugin Name	Creator	Description
Clear Costmap	Eitan Marder-Eppstein	A service to clear the given costmap in case of incorrect perception or robot is stuck
Spin	Steve Macenski	Rotate behavior of configurable angles to clear out free space and nudge robot out of potential local failures
Back Up	Brian Wilcox	Back up behavior of configurable distance to back out of a situation where the robot is stuck
Wait	Steve Macenski	Wait behavior with configurable time to wait in case of time based obstacle like human traffic or getting more sensor data
Drive On Heading	Joshua Wallace	Drive on heading behavior with configurable distance to drive
Assisted Teleop	Joshua Wallace	AssistedTeleop behavior that scales teleop commands to prevent collisions.

Waypoint Task Executors

Plugin Name	Creator	Description
WaitAtWaypoint	Fetullah Atas	A plugin to execute a wait behavior on waypoint arrivals.
PhotoAtWaypoint	Fetullah Atas	A plugin to take and save photos to specified directory on waypoint arrivals.
InputAtWaypoint	Steve Macenski	A plugin to wait for user input before moving onto the next waypoint.

Goal Checkers

Plugin Name	Creator	Description
SimpleGoalChecker	David Lu!!	A plugin check whether robot is within translational distance and rotational distance of goal.
StoppedGoalChecker	David Lu!!	A plugin check whether robot is within translational distance , rotational distance of goal, and velocity threshold.

Progress Checkers

Plugin Name	Creator	Description
SimpleProgressChecker	David Lu!!	A plugin to check whether the robot was able to move a minimum distance in a given time to make progress towards a goal

Behavior Tree Nodes

Action Plugin Name	Creator	Description
Back Up Action	Michael Jeronimo	Calls backup behavior action
Drive On Heading Action	Joshua Wallace	Calls drive on heading behavior action
Assisted Teleop Action	Joshua Wallace	Calls assisted teleop behavior action
Clear Entire Costmap Service	Carl Delsey	Calls clear entire costmap service
Clear Costmap Except Region Service	Guillaume Doisy	Calls clear costmap except region service
Clear Costmap Around Robot Service	Guillaume Doisy	Calls clear costmap around robot service
Compute Path to Pose Action	Michael Jeronimo	Calls Nav2 planner server
Smooth Path Action	Matej Vargovcik	Calls Nav2 smoother server
Follow Path Action	Michael Jeronimo	Calls Nav2 controller server
Navigate to Pose Action	Michael Jeronimo	BT Node for other BehaviorTree.CPP BTs to call Navigation2 as a subtree action
Reinitalize Global Localization Service	Carl Delsey	Reinitialize AMCL to a new pose
Spin Action	Carl Delsey	Calls spin behavior action
Wait Action	Steve Macenski	Calls wait behavior action
Truncate Path	Francisco Martín	Modifies a path making it shorter
Truncate Path Local	Matej Vargovcik	Extracts a path section around robot
Planner Selector	Pablo Iñigo Blasco	Selects the global planner based on a topic input, otherwises uses a default planner id
Controller Selector	Pablo Iñigo Blasco	Selects the controller based on a topic input, otherwises uses a default controller id
Goal Checker Selector	Pablo Iñigo Blasco	Selects the goal checker based on a topic input, otherwises uses a default goal checker id
`Smoother Selector`_	Owen Hooper	Selects the smoother based on a topic input, otherwises uses a default smoother id
Navigate Through Poses	Steve Macenski	BT Node for other BehaviorTree.CPP BTs to call Nav2’s NavThroughPoses action
Remove Passed Goals	Steve Macenski	Removes goal poses passed or within a tolerance for culling old viapoints from path re-planning
Compute Path Through Poses	Steve Macenski	Computes a path through a set of poses rather than a single end goal pose using the planner plugin specified
Cancel Control Action	Pradheep Padmanabhan	Cancels Nav2 controller server
Cancel BackUp Action	Pradheep Padmanabhan	Cancels backup behavior action
Cancel Spin Action	Pradheep Padmanabhan	Cancels spin behavior action
Cancel Wait Action	Pradheep Padmanabhan	Cancels wait behavior action
Cancel Drive on Heading Action	Joshua Wallace	Cancels drive on heading behavior action
Cancel Assisted Teleop Action	Joshua Wallace	Cancels assisted teleop behavior action

Condition Plugin Name	Creator	Description
Goal Reached Condition	Carl Delsey	Checks if goal is reached within tol.
Goal Updated Condition	Aitor Miguel Blanco	Checks if goal is preempted.
Globally Updated Goal Condition	Joshua Wallace	Checks if goal is preempted in the global BT context
Initial Pose received Condition	Carl Delsey	Checks if initial pose has been set
Is Stuck Condition	Michael Jeronimo	Checks if robot is making progress or stuck
Transform Available Condition	Steve Macenski	Checks if a TF transformation is available. When succeeds returns success for subsequent calls.
Distance Traveled Condition	Sarthak Mittal	Checks is robot has traveled a given distance.
Time Expired Condition	Sarthak Mittal	Checks if a given time period has passed.
Is Battery Low Condition	Sarthak Mittal	Checks if battery percentage is below a specified value.
Is Path Valid Condition	Joshua Wallace	Checks if a path is valid by making sure there are no LETHAL obstacles along the path.
Path Expiring Timer	Joshua Wallace	Checks if the timer has expired. The timer is reset if the path gets updated.

Decorator Plugin Name	Creator	Description
Rate Controller	Michael Jeronimo	Throttles child node to a given rate
Distance Controller	Sarthak Mittal	Ticks child node based on the distance traveled by the robot
Speed Controller	Sarthak Mittal	Throttles child node to a rate based on current robot speed.
Goal Updater	Francisco Martín	Updates the goal received via topic subscription.
Single Trigger	Steve Macenski	Triggers nodes/subtrees below only a single time per BT run.
PathLongerOnApproach	Pradheep Padmanabhan	Triggers child nodes if the new global path is significantly larger than the old global path on approach to the goal

Control Plugin Name	Creator	Description
Pipeline Sequence	Carl Delsey	A variant of a sequence node that will re-tick previous children even if another child is running
Recovery	Carl Delsey	Node must contain 2 children and returns success if first succeeds. If first fails, the second will be ticked. If successful, it will retry the first and then return its value
Round Robin	Mohammad Haghighipanah	Will tick i th child until a result and move on to i+1