BARRETT Drive systems

WAM® Arm

Direct-drive, zero-backlash manipulator with Transparent Dynamics™ — 1 m reach, 4-DOF and 7-DOF, from 50 W.

TRANSPARENT DYNAMICS™

The WAM® Arm is a highly dexterous, naturally backdrivable manipulator, cited in the Millennium Edition of the Guinness World Records, pp170-171, as the world’s “most advanced” robotic arm. The only arm sold in the world with direct-drive capability supported by Transparent Dynamics™ between the motors and joints, so its control of contact forces is robust—independent of mechanical force or torque sensors. It is built to outperform conventional robots with unmatched human-like grace and dexterity.

The world’s most advanced robot arm

The WAM® Arm is available in two main configurations, 4-degree-of-freedom and 7-degree-of-freedom, both with human-like kinematics. The joint ranges exceed those for conventional robotic arms.

4-DOF or 7-DOF, one platform

Modularity

Performance

Matching advanced electronics with inherently backdrivable cable drives results in superbly graceful motions, like this video of learning to juggle. Barrett owns the technology for the highest performance servo-electronics available in the world today. These electronics are also the smallest (16 grams) and most power-efficient servo-drive electronics available today.

Higher performance than conventional manipulators

See it in action

The WAM in motion

See it work How it works

Ultra high speedThe high-speed option, timed against a reference clock.

Mobile manipulationA WAM on a mobile base working through a real kitchen task.

Healthcare and assistiveDirect physical assistance, where backdrivability matters most.

Partner jugglingA human and the WAM share a sustained three-ball cascade.

BackdrivabilityWhy the arm yields to contact instead of resisting it.

Gearless drivesCable transmission in place of gearboxes, so no backlash.

Portability and modularity4-DOF and 7-DOF from the same platform.

The Puck insideThe motor controller that makes the joints this compact.

Dynamic manipulation

Five-ball juggling, two WAMs — ISRR 2026 Human–robot partner juggling — IROS 2026 WAM as low-inertia benchmark — Science Robotics 2026

Space robotics

NASA JPL Ocean Worlds testbed Bayesian kinematic calibration — ICRA 2025 Active-learning calibration — ICRA 2023

Teleoperation & haptics

Transparency-optimized bilateral control — Frontiers 2026 Sensorless four-channel architecture — preprint Transparent WAM teleoperation — project page

Learning & manipulation

Temporal Policy, learning from demos — IROS 2026 Sub-0.25 mm assembly by compliance — ICRA 2023 Dynamic cloth manipulation — IEEE TCST 2024

Whats in the box?

System components

a version for every application

WAM Configurations

    
          Standard
          High SpeedUltra High Speed
          High Payload
          High Precision
        
          Peak endtip velocity
          3 m/s
          5 m/s15 m/s ultra
          3 m/s
          3 m/s
        
          Payload 4‑DOF / 7‑DOF
          4 / 3 kg
          4 / 3 kg
          8 / 6 kg
          4 / 3 kg
        
          Repeatability 4‑DOF / 7‑DOF
          1000 / 2000 µm
          1000 / 2000 µm
          1000 / 2000 µm
          100 / 200 µm
        
          DC input
          24–80 V
          48–160 Vultra only
          24–80 V
          24–80 V
        
            Every configuration: 1 m reach, a 3.5 m³ spherical
            workspace, and 50 W active power — low for this size,
            because the cable drive needs no gearboxes to hold position.
            Mass 25 kg (4‑DOF) / 27 kg (7‑DOF).
            Orange marks what each configuration upgrades.

Ready to put a WAM in your lab?

Configurations, lead times, and quotes - we answer in one business day.

Email Sales@barrett.com