Force control is the capability that separates a robot that can move objects from one that can assemble them. When a robot inserts a connector, meshes gears, or drives a screw, it must sense contact forces and respond in real time. Two Chinese platforms address this differently: Fourier Intelligence’s GR-2 humanoid and Rokae’s HumanX arm system.
Why Force Control Matters
A robot without force sensing is a position controller — it moves to a programmed position regardless of what it encounters. For precisely located parts with known geometry, position control works. For anything requiring compliance — pushing until a click, screwing to a torque threshold, inserting a shaft until it seats — position control fails. The robot either damages the part or misses the assembly. Force control adds a second loop: the robot measures force at its end effector and adjusts motion to maintain a target force rather than a target position.
Fourier GR-2: Full-Body Force Sensing
All 40 joints on GR-2 include torque sensors. The robot detects and responds to contact at any point on its body. Wrist F/T specs: ±200 N force range, ±15 Nm torque range, 0.1 N resolution, 1 kHz update rate. Fourier’s impedance control allows independent stiffness per Cartesian axis — high stiffness vertically for pressing operations, low stiffness laterally for insertion alignment.
Rokae HumanX: Precision Fixed-Station Architecture
HumanX is a two-arm torso without legs — optimized for fixed workstation deployment. All 7 DOF per arm have torque sensors. Specs: 0.05 N resolution, 2 kHz update rate. The 2 kHz versus GR-2’s 1 kHz matters for high-speed insertion: at 2 kHz, contact detection within 0.5 ms; at 1 kHz, worst case is 1 ms. For a robot arm moving at 500 mm/s, that 0.5 ms difference represents 0.25 mm of additional travel after contact — enough to matter for precise insertions into tight-tolerance holes or sockets.
Comparison
Force sensing coverage: GR-2 covers all 40 joints plus wrist; HumanX covers all 14 arm joints. Wrist F/T resolution: GR-2 at 0.1 N, HumanX at 0.05 N. Sensor update rate: GR-2 at 1 kHz, HumanX at 2 kHz. Contact detection latency: GR-2 under 1 ms, HumanX under 0.5 ms. GR-2 is mobile (bipedal); HumanX is fixed base.
Which to Choose
Use GR-2 when the task requires mobility between workstations, full-body compliance matters in human-shared spaces, or the application is diverse enough that general humanoid capability is worth the force control tradeoff. Use HumanX when the application is a fixed workstation, force thresholds are below 1 N, contact response speed is critical, or existing workcell infrastructure makes mobile operation unnecessary. For pure precision assembly — PCB connectors, screw driving to torque spec, bearing insertion — HumanX has a clear technical edge. For tasks combining assembly with transport or multi-station workflows, GR-2’s mobility is the only viable option.
Full humanoid ranking: Top 40 China Robot Rankings 2025. Factory profiles: robots manufacturer in China.
Sources
- Fourier Intelligence GR-2 technical documentation (2025)
- Rokae HumanX product specification sheet (2025)
- ESM China: Force control robot comparison China market 2025
