Locomotion

Frontal Plane Control

Frontal plane control is the regulation of a legged robot's lateral balance and motion within the frontal (coronal) plane, the vertical plane dividing front from back, covering side-to-side center-of-mass sway, hip abduction and adduction, and lateral foot placement. Bipedal walking exhibits naturally unstable lateral rocking between support feet, so controllers stabilize it through lateral stepping strategies, ankle inversion torques, and step-width regulation, often analyzed separately from sagittal plane dynamics.

Why it matters for physical AI

Lateral balance failures cause sideways falls that sagittal-plane analysis never predicts; explicit frontal plane treatment is essential for humanoids stepping in cluttered, narrow spaces around humans.