Locomotion

Foot Clearance

Foot clearance is the height by which a legged robot's swing foot passes above the ground or obstacles during the swing phase of a gait. Insufficient clearance causes trips and scuffs on uneven terrain, while excessive clearance wastes energy and slows the gait. Controllers regulate clearance through swing trajectory design, and learned locomotion policies are often shaped with clearance rewards or terrain-aware foot placement to traverse rubble and stairs.

Why it matters for physical AI

Trips on unseen ground are a leading failure mode for legged deployment; clearance behavior encodes how well a policy has internalized terrain geometry versus merely memorizing flat-ground gaits.