Software & Middleware

Behavior Tree

A behavior tree is a hierarchical task-control architecture in which a tree of composite nodes, such as sequences, fallbacks, and parallels, ticks leaf nodes that perform actions or check conditions, returning success, failure, or running status upward. Originating in game AI, behavior trees became standard in robotics through implementations like BehaviorTree.CPP, which orchestrates the ROS 2 Nav2 stack, offering modularity and reactive execution that finite state machines handle poorly.

Why it matters for physical AI

Deployed systems still need interpretable orchestration above learned skills, and behavior trees are a dominant pattern for sequencing policies, handling failures, and encoding recovery logic that operators can audit.