Recovery Behavior Trees in Nav2

Source: ros2-copilot-skills recovery BT skill

Why This Matters

Recovery design is where a navigation stack shows whether it understands failure or merely reacts to it. A good recovery tree turns known failure modes into deliberate responses; a poor one just cycles through motions until the operator gives up.

Distilled Takeaways

• Recovery trees should reflect likely failure causes, not just a generic list of fallback actions.
• Different failures call for different responses: perception refresh, local escape, patience, or escalation.
• The recovery subtree is part of the robot's autonomy architecture, not a patch at the end.
• Metrics and traces matter because recovery quality is hard to judge from one incident.

Practical Guidance

• Design recovery around specific classes of failure you have actually observed.
• Keep escalation logic explicit so the tree does not loop blindly.
• Pair each recovery action with the failure mode it is supposed to address.
• Review recovery traces after real failures and refine the tree intentionally.

Corroborating References

• Nav2 behavior tree docs
• BehaviorTree.CPP docs

When to Read the Original Source

Go to the original skill when you want concrete recovery-tree structuring advice and examples of how to sequence wait, backup, spin, and related actions coherently.