Hardware

Ball Bearing

A ball bearing is a rolling-element bearing that supports rotating shafts by interposing hardened steel or ceramic balls between inner and outer races, replacing sliding friction with much lower rolling friction. Variants include deep-groove bearings for radial loads, angular-contact pairs for combined loads, and thin-section and crossed-roller types used in robot joints where space is tight and moment stiffness matters.

Why it matters for physical AI

Joint stiffness, friction, and lifetime trace back to bearing selection, and bearing friction is part of the unmodeled dynamics that simulation-trained policies must be robust to when transferred onto real hardware.