Humble to Iron
Moving from ROS 2 Humble to Iron, a number of stability improvements were added that we will not specifically address here.
Added Collision Monitor
PR 2982 adds new safety layer operating independently of Nav2 stack which ensures the robot to control the collisions with near obstacles, obtained from different sensors (LaserScan, PointCloud, IR, Sonars, etc…). See Collision Monitor for more details. It is not included in the default bringup batteries included from nav2_bringup.
Removed use_sim_time from yaml
PR #3131 makes it possible to set the use_sim_time parameter from the launch file for multiple nodes instead of individually via the yaml files. If using the Nav2 launch files, you can optionally remove the use_sim_time parameter from your yaml files and set it via a launch argument.
Run-time Speed up of Smac Planner
The core data structure of the graph implementation in the Smac Planner framework was swapped out in PR 3201 to using a specialized unordered map implementation. This speeds up the planner by 10% on trivial requests and reports up to 30% on complex plans that involve numerous rehashings.
Recursive Refinement of Smac and Simple Smoothers
The number of recursive refinements for the Simple and Smac Planner Smoothers have been exposed under the refinement_num parameter. Previous behavior had this hardcoded if do_refinement = True to 4. Now, default is 2 to help decrease out-of-the-box over smoothing reducing in paths closer to collision than probably ideal, but old behavior can be achieved by changing this to 4.
Simple Commander Python API
PR 3159 and follow-up PRs add in Costmap API in Python3 simple commander to receive OccupancyGrid messages from Nav2 and be able to work with them natively in Python3, analog to the C++ Costmap API. It also includes a line iterator and collision checking object to perform footprint or other collision checking in Python3. See the Simple Commander API for more details.
Smac Planner Start Pose Included in Path
PR 3168 adds the starting pose to the Smac Planners that was previously excluded during backtracing.
Parameterizable Collision Checking in RPP
PR 3204 adds makes collision checking for RPP optional (default on).
Expanded Planner Benchmark Tests
PR 3218 adds launch files and updated scripts for performing objective random planning tests across the planners in Nav2 for benchmarking and metric computation.
Smac Planner Path Tolerances
PR 3219 adds path tolerances to Hybrid-A* and State Lattice planners to return approximate paths if exact paths cannot be found, within a configurable tolerance aroun the goal pose.
costmap_2d_node default constructor
PR #3222 changes the constructor used by the standalone costmap node. The new constructor does not set a name and namespace internally so it can be set via the launch file.
Costmap Filters
Costmap Filters now are have an ability to be enabled/disabled in run-time by calling toggle_filter service for appropriate filter (PR #3229).
Added new binary flip filter, allowing e.g. to turn off camera in sensitive areas, turn on headlights/leds/other safety things or switch operating mode when robot is inside marked on mask areas (PR #3228).
Savitzky-Golay Smoother
Adding a new smoother algorithm, the Savitzky-Golay smoother to the smoother server plugin list. See the configuration guide Savitzky-Golay Smoother for more details.
Changes to Map yaml file path for map_server node in Launch
PR #3174 adds a way to set the path to map yaml file for the map_server node either from the yaml file or using the launch configuration parameter map giving priority to the launch configuration parameter. yaml_filename is no longer strictly required to be present in nav2_params.yaml.
SmootherSelector BT Node
PR #3283 adds a BT node to set the smoother based on a topic or a default. See the configuration guide Simple Smoother for more details.
Publish Costmap Layers
PR #3320 adds the ability for the nav2_costmap_2d package to publish out costmap data associated with each layer.
Give Behavior Server Access to Both Costmaps
PR #3255 adds the ability for a behavior to access the local and global costmap.
To update behaviors, any reference to the global_frame must be updated to the local_frame parameter
along with the configuration method which now takes in the local and global collision checkers.
Lastly, getResourceInfo must be overridden to return CostmapInfoType::LOCAL. Other options include GLOBAL if the behavior useses global costmap and/or footprint)
or BOTH if both are required. This allows us to only create and maintain the minimum amount of expensive resources.
New Model Predictive Path Integral Controller
The new Nav2 MPPI Controller is a predictive controller - a successor to TEB and pure path tracking MPC controllers - with Nav2. It uses a sampling based approach to select optimal trajectories, optimizing between successive iterations. It contains plugin-based objective functions for customization and extension for various behaviors and behavioral attributes.
See the README.md and Model Predictive Path Integral Controller page for more detail.
Behavior Tree Uses Error Codes
PR #3324 adds three new condition nodes to check for error codes on the blackboard set by action BT nodes which contain them.
The AreErrorCodesPresent condition node allows the user to specify the error code from the server along with the error codes to match against.
The WouldAControllerRecoveryHelp checks if the active error code is UNKNOWN, PATIENCE_EXCEEDED, FAILED_TO_MAKE_PROGRESS or NO_VALID_CONTROL.
If the error code is a match, the condition returns SUCCESS.
These error code are potentially able to be cleared by a controller recovery.
The WouldAPlannerRecoveryHelp checks if the active error code is UNKNOWN, NO_VALID_CONTROL, or TIMEOUT.
If the error code is a match, the condition returns SUCCESS.
These error code are potentially able to be cleared by a planner recovery.
The WouldASmootherRecoveryHelp checks if the active error code is UNKNOWN, TIMEOUT, FAILED_TO_SMOOTH_PATH, or SMOOTHED_PATH_IN_COLLISION.
If the error code is a match, the condition returns SUCCESS.
These error code are potentially able to be cleared by a smoother recovery.
DWB Forward vs Reverse Pruning
PR #3374 adds a new forward_prune_distance parameter in the DWB controller. It replaces the prune_distance for forward path shortening, enabled through the shorten_transformed_plan boolean parameter. This change allows to use different values for forward and backward path shortening.
More stable regulation on curves for long lookahead distances
PR #3414 adds a new use_fixed_curvature_lookahead parameter to the RPP controller. This makes slowing down on curve not dependent on the instantaneous lookahead point, but instead on a fixed distance set by the parameter curvature_lookahead_dist.
Publish Collision Monitor State
PR #3504 adds a new state_topic parameter to the CollisionMonitor. If specified, this optional parameter enables the state topic publisher. The topic reports the currently activated polygon action type and name.
Renamed ROS-parameter in Collision Monitor
PR #3513 renames max_points parameter to min_points and changes its meaning. Formerly max_points meant the maximum number of points inside the area still not triggering the action, while min_points - is a minimal number of points starting from the action to be initiated. In other words min_points now should be adjusted as max_points + 1.
New safety behavior model “limit” in Collision Monitor
PR #3519 adds a new collision monitor behavior model limit that restricts maximum linear and angular speed to specific values (linear_limit and angular_limit) if enough points are in the given shape.
Velocity smoother applies deceleration when timeout
PR #3512 makes the VelocitySmoother apply the deceleration when the input command timeout.
PoseProgressChecker plugin
PR #3530 adds a new nav2_controller::PoseProgressChecker plugin. It builds on the behavior of the SimpleProgressChecker by adding a new parameter required_movement_angle, allowing the plugin to considers that there is still progress when there is no translation movement, from the moment there is a rotation movement superior to required_movement_angle within the movement_time_allowance.
Allow multiple goal checkers and change parameter progress_checker_plugin(s) name and type
PR #3555 initializes the progress checker plugin(s) in the same way as for the goal checker and controller plugins: it is now a list of string and was renamed from progress_checker_plugin to progress_checker_plugins, and the type changed from string to vector<string>. This allows the initialization of multiple progress checkers that can be chosen from the added progress_checker_id field of the FollowPath action.
Beware that it is a breaking change and that configuration files will need to be updated.
IsBatteryChargingCondition BT Node
PR #3553 adds a BT node to check if the battery is charging. See the configuration guide IsBatteryCharging for more details.
Behavior Server Error Codes
PR #3569 updates the behavior server plugins to provide error codes on failure.
Spin: NONE: 0, UNKNOWN: 701, server error codes: 701-709
BackUp: NONE: 0, UNKNOWN: 801, server error codes: 710-719
DriveOnHeading: NONE: 0, UNKNOWN: 901, server error codes: 720-729
AssistedTeleop: NONE: 0, UNKNOWN: 1001, server error codes: 730-739
New Denoise Costmap Layer Plugin
PR #2567 adds the new plugin for filtering noise on the costmap.
Due to errors in Voxel Layer or Obstacle Layer measurements, salt and pepper noise may appear on the costmap. This noise creates false obstacles that prevent the robot from finding the best path on the map.
The new Denoise Layer plugin is designed to filter out noise-induced standalone obstacles or small obstacles groups. This plugin allows you to add layer that will filter local or global costmap.
More information about Denoise Layer plugin and how it works could be found here.