git:20260907.863840e to git:20260919.498ea4e

6 added, 1 removed. Audit A to A.

---

name: navigation

- description: Build and debug ROS 2 robot navigation with Nav2.

+ description: Configure, extend, and debug Nav2 in an existing robot app; explain navigation concepts. New mapping/localization/navigation demos start with architect.

---

# Navigation

Treat Nav2 as a **navigation chain**. Find the first link whose evidence is

wrong.

## Start from the robot

+ - For a new app or first demo, read [architect](../architect/SKILL.md) before

+ scaffolding or installing a navigation stack. It finds the saved apps checkout

+ and selects a compatible baseline, even from outside the Robium workspace.

+ If that selection already happened, continue here. Existing-app fixes and

+ navigation explanations do not need onboarding.

- Read the running system and its repository before proposing a new stack.

- Identify the ROS distribution, installed Nav2 version, launch topology, and

parameter files from the environment itself.

- Note the robot's motion model, footprint, sensors, frames, command interface,

and whether it is using SLAM or a saved map.

- Start from the robot vendor's matching configuration. Change only what the

application has outgrown.

## Trace the chain

- **Environment:** the installed packages, launch files, parameters, and

running graph describe the same stack.

- **Pose:** clock and transforms are fresh; one localizer owns `map -> odom`;

odometry owns the path from `odom` to the robot base.

- **World:** the map and live sensors reach both costmaps in frames they can

transform.

- **Plan:** the navigation action accepts the goal and the planner produces a

path in the intended frame.

- **Control:** the controller receives that path and can produce a valid motion

command for the robot's kinematics and footprint.

- **Base:** command topic, message type, smoothing or safety nodes, and base

driver agree end to end.

- Change the first broken link, then re-check what depends on it.

## Go deeper only when needed

- If navigation is failing and the broken link is unclear, read

[FAILURES.md](FAILURES.md).

- If the stack is TurtleBot3 on ROS 2 Jazzy with Gazebo Harmonic, read

[TURTLEBOT3-JAZZY-GAZEBO.md](TURTLEBOT3-JAZZY-GAZEBO.md) before changing its

launch or parameters.

- For distribution-sensitive parameters, behavior trees, or custom Nav2

plugins, inspect the matching installed source and current official Nav2

documentation.

- Reach for ROS 2 guidance when the evidence points to discovery, QoS, TF, or

package wiring; Gazebo guidance for simulation, spawning, sensors, or

bridges; and RViz2 or Foxglove guidance for viewer behavior.

## Done

- Verify the changed link and the user-visible outcome: the intended goal

completes on the actual robot or representative simulation.

- If the chain cannot be completed, name the first unsupported link and the

evidence still needed.