Hardware

Cycloidal Drive

A cycloidal drive is a compact, high-ratio gear reducer in which an eccentric input drives a cycloidal disc that rolls against ring pins, producing output rotation with high shock-load tolerance, high torsional stiffness, and low backlash. Compared to harmonic drives, cycloidal reducers handle higher impact loads and offer greater rigidity at the cost of more mass and slight torque ripple, making them common in the proximal joints of industrial robots.

Why it matters for physical AI

Reducer choice shapes a joint's stiffness, backlash, efficiency, and impact survivability, all of which condition the dynamics that learned controllers must master and the abuse hardware tolerates in deployment.