easynav_navmap_planner Directory Reference

Directory dependency graph for easynav_navmap_planner:

Directories
	include
	src

Detailed Description

easynav_navmap_planner

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Description

A* path planner operating over a NavMap triangular mesh.
The planner computes the minimum-cost path between the robot and the goal, taking into account both the geometric distance between triangles and the cost values stored in a selected NavMap layer (typically "inflated_obstacles").

Instead of simply avoiding non-free NavCels, the planner integrates their cost values (0–255) into the path evaluation. Cells marked as LETHAL_OBSTACLE or NO_INFORMATION are considered non-traversable, while inflated or inscribed cells are allowed but penalized proportionally to their cost.

This enables smoother and safer trajectories that still respect proximity constraints imposed by obstacle inflation.

Cost model

For two neighboring NavCels u and v, the edge cost is computed as:

[ \text{cost}(u,v) = d(u,v) \times \left(\text{cost_factor} + \text{inflation_penalty} \times \frac{c(v)}{253}\right) ]

where d(u,v) is the Euclidean distance between triangle centroids,
and c(v) is the cost value of cell v.
This formulation ensures that:

• cells near obstacles (high cost) are traversed only if geometrically necessary,
• lethal (254) and unknown (255) cells are not traversable.

Authors and Maintainers

• Authors: Intelligent Robotics Lab
• Maintainers: Francisco Martín Rico fmric.nosp@m.o@gm.nosp@m.ail.c.nosp@m.om

Supported ROS 2 Distributions

Distribution	Status
humble
jazzy
kilted
rolling

Plugin (pluginlib)

• Plugin Name: easynav_navmap_planner/AStarPlanner
• Type: easynav::navmap::AStarPlanner
• Base Class: easynav::PlannerMethodBase
• Library: easynav_navmap_planner
• Description: A* path planner over a NavMap triangular mesh using per-cell costs to compute the shortest safe path.

Parameters

All parameters are declared under the plugin namespace, i.e.
/<node_fqn>/easynav_navmap_planner/AStarPlanner/...

Name	Type	Default	Description
<plugin>.cost_factor	double	2.0	Multiplicative weight for geometric distance; values > 1 increase the relative importance of distance.
<plugin>.continuous_replan	bool	true	If true, recomputes the path whenever NavState updates; if false, plans once per goal.

Note: The planner internally uses hardcoded values for layer_name (prefers "inflated_obstacles", fallback to "obstacles"), inflation_penalty (value used in cost calculation), cost_axial, and cost_diagonal. These are not runtime-configurable parameters.

Interfaces (Topics and Services)

Publications

Direction	Topic	Type	Purpose	QoS
Publisher	<node_fqn>/<plugin>/path	nav_msgs/msg/Path	Publishes the computed A* path.	depth=10

This plugin does not create subscriptions or services directly; it retrieves all inputs from NavState.

NavState Keys

Key	Type	Access	Description
goals	nav_msgs::msg::Goals	Read	Target pose(s) for path planning.
robot_pose	nav_msgs::msg::Odometry	Read	Current robot pose (start position).
map.navmap	::navmap::NavMap	Read	NavMap containing geometry and cost layer. The planner reads costs from the layer specified in <plugin>.layer (default: "inflated_obstacles"). If that layer does not exist, it automatically falls back to "obstacles".
path	nav_msgs::msg::Path	Write	Output path, computed as the lowest-cost route.

TF Frames

The planner assumes frame consistency between NavMap, robot pose, and goals. No TF lookups are performed internally.

License

Apache-2.0