Who Builds the Actuator? Inside the Global Supply Chain of Every Robot Joint

The "eyes" of the motor — precision sensors that measure rotor position and speed. Without accurate feedback, the robot cannot control its movements.

The core electromagnetic drive — stator and rotor without housing, designed to be integrated directly into the joint. High torque density is the competitive moat.

The invisible force — neodymium magnets embedded in the rotor that create the magnetic field. This is where China holds the most leverage, controlling ~60% of global rare-earth processing.

The torque multiplier — precision gearboxes that reduce motor speed while increasing output torque. German engineering dominates this segment, though Chinese firms are rapidly closing the gap.

Note: Some robots use strain-wave (harmonic) or cycloidal drives instead of planetary gears.

The silent workhorse — precision bearings that allow smooth rotation under load. Japanese and European manufacturers dominate this century-old industry.