Humanoid Joint Actuators
CategoryActuators
Market classPrototype
Introduction date11 August 2022
4 components
Deployed
Actuators·Boston Dynamics
Atlas Electric Actuator (Boston Dynamics, 2024)
Boston Dynamics' proprietary joint actuator used in the fully-electric Atlas (2024+) — high torque density and 360° continuously rotating joints.
TorqueNot disclosed; Boston Dynamics reports higher torque density than the hydraulic Atlas generation
DOFStosowany w ok. 28 stopniach swobody robota Atlas (2024+); część stawów rotuje ciągle przez 360°
Deployed
Actuators
Fourier Smart Actuator (FSA)
Integrated PMSM joint actuator with reducer, driver and absolute encoder used in Fourier GR-1 and GR-2 humanoid robots.
TorquePeak up to ~230 N·m (largest variant in the portfolio)
PrecisionAbsolute encoder on both input and output shaft
Voltage48 V DC
Deployed
Actuators·Tesla
Tesla Optimus Roller Screw Linear Actuator
Tesla's planetary roller-screw linear actuator — 14 units in the legs of Optimus Gen 2, shock- and brinelling-resistant.
PrecisionHigh-resolution linear position encoder + torque-mode control
Prototype
Joints·Xiaomi
Xiaomi Self-Developed Humanoid Joint Motor (CyberOne)
Family of Xiaomi’s self-developed humanoid joint motors built for the CyberOne prototype (2022). The strongest variant (knee) reaches a peak torque of 300 Nm; the robot has 21 total degrees of freedom.
Last updated: 23 March 2026