Fourier Smart Actuator (FSA) is a family of integrated joint actuators designed by Fourier Intelligence for the GRx humanoid robot series. Each module combines a brushless PMSM motor, planetary or harmonic reducer, power-stage driver with current loop, absolute input- and output-shaft encoders and a communication interface inside a single sealed housing.
The FSA architecture lets Fourier ship the GR-1 humanoid with 40 degrees of freedom and the GR-2 with 53 DoF, while every joint uses the same replaceable module in one of several peak-torque sizes (from a few dozen up to more than 200 N·m). Modularity enables service without per-joint recalibration.
PMSM Joint Actuator · serves as: Joint Actuation, Precision Joint Motion, Torque Transmission, Closed-Loop Drive Control. · compatible with: Humanoid, Biped, Research Robot.
Which group Fourier Smart Actuator (FSA) belongs to and how it is built
A PMSM (Permanent Magnet Synchronous Motor) joint actuator is an integrated drive module that uses a permanent magnet synchronous motor to provide precise position, velocity, and torque control at robot joints. It offers high power density, low losses, and deterministic torque response, making it a popular choice in robotic manipulators, exoskeletons, and humanoid robots. The unit typically integrates an encoder, gearbox, and motor controller into a single compact assembly.
Basic physical properties of Fourier Smart Actuator (FSA) — dimensions, weight and materials
