Hardware

Tendon-Driven Actuation

Tendon-driven actuation is a transmission scheme in which motors move a robot's joints remotely through cables or tendons routed over pulleys and through sheaths, allowing actuators to be placed away from the joints they drive. This keeps distal links light, which is why tendon drives dominate anthropomorphic hand designs, including the Shadow Hand, and appear in some full arms and surgical robots. Drawbacks include friction, elasticity, creep, and the need for tension maintenance and periodic recalibration.

Why it matters for physical AI

Lightweight, human-proportioned hands and arms for humanoids depend on remote actuation, and the compliance and friction of tendon transmissions shape both the control problem and the sim-to-real gap for dexterous manipulation policies.