Locomotion

Central Pattern Generator (CPG)

A central pattern generator is a neural circuit, biological or artificial, that produces rhythmic output without requiring rhythmic input, underlying gaits like walking and swimming in animals. In robotics, CPGs are implemented as coupled nonlinear oscillators whose phase relationships define gait patterns, providing smooth, stable rhythms modulated by simple high-level signals. Ijspeert's salamander robot work is a landmark demonstration, and CPG layers still appear beneath learned locomotion policies.

Why it matters for physical AI

CPGs offer a compact, stable action space for legged locomotion learning: policies modulate oscillator parameters instead of raw torques, improving sample efficiency and sim-to-real robustness for gait control.