Why finite‑state machines (FSMs) matter

Finite‑state machines (FSMs) capture discrete behavior: a system is in one state at a time and moves to another when a condition is met. This makes complex behavior easy to describe, visualize, and test.

In robotics and autonomous vehicles, FSMs are used to orchestrate high‑level behaviors and safety logic:

• Driving modes such as Follow, Change lane, and Stop based on perception events (vehicle ahead, lane clear, traffic light red/green).
• Supervisors that gate actions and enforce safe fallbacks when sensors disagree or confidence is low.
• Task sequencing for manipulation, navigation, docking, and recovery behaviors.

FSMs combine naturally with continuous controllers: the FSM selects which controller is active, while controllers handle the low‑level dynamics. Because the states and transitions are explicit, engineers can reason about corner cases and verify that unsafe transitions are impossible.