Boston Dynamics unveiled a new hand for its Atlas humanoid — four digits and 13 degrees of freedom, up from seven. The company deliberately dropped the pinky to cut cost and failure points. The stated goal is manufacturing 100,000 units a year.
Key takeaways
- 13 degrees of freedom per hand, up from 7 in the previous generation
- Three fingers with 3 DoF each plus a thumb with four
- Dense pressure sensors across the fingertips and palm
- Actuators sit directly in the joints, with no tendons or cables
- Target production scale: 100,000 hands per year
Four digits instead of five
The design has three fingers and a thumb. Each finger got three degrees of freedom, the thumb four. That makes 13, nearly double the previous generation.
The pinky was cut on purpose. Engineers taped their own ring and little fingers together and checked what stopped being possible. Not much.
In exchange, cost, volume and the number of breakable parts all dropped.
Hands are a ruthless design tradeoff. There's no way around it, you're always giving up on something.
Alberto Rodriguez, director responsible for Atlas robot behaviour at Boston Dynamics.
| Parameter | Value |
|---|---|
| Digits | three fingers and a thumb |
| Degrees of freedom | 13 (3 × 3 in the fingers, 4 in the thumb) |
| Previous generation | 7 degrees of freedom |
| Actuation | direct drive, built into the joints |
| Sensing | dense pressure grid on fingertips and palm |
| Target scale | 100,000 units per year |
Direct drive instead of tendons
There are no tendons and no externally routed cables. The hand uses direct drive?Direct drive: A motor placed straight in the joint, with no tendons, belts or intermediate gearing. Fewer parts that stretch and wear out., and each actuator pack is a single replaceable module.
The joints are backdrivable?Backdrivable: A joint that yields and rotates under external force instead of locking up and passing the impact into the gearbox. — they give way on impact rather than passing force deeper into the mechanism. That matters for reinforcement learning, where the robot hits its surroundings over and over.
Finger splaying and a dense grid of pressure sensors round out the design.
Atlas's previous grippers were strong but crude. According to Boston Dynamics they survived handstands and held the robot's own 90 kg.
Scale before anthropomorphism
The priority was not resemblance to a human hand but reliability and manufacturability at 100,000 units a year.
Part of the market is going the other way. Unitree priced its 22-degree-of-freedom Dex5-S hand at $6,500. More fingers and joints also mean more things to service.
Why it matters
The hand is the hardest subsystem on a humanoid and the most common point of failure. Boston Dynamics' decision marks a shift from demo phase to production phase, where unit cost and mean time between failures matter more than the joint count on a spec sheet.
A four-digit hand concedes that full anthropomorphism does not yet pay off. If the direction holds, simplified hands will become the factory standard.
What's next
- Boston Dynamics promised further material on the new gripper on its company blog, with no date given
- Atlas already works at the Hyundai plant in Georgia, where 25,000 robots are eventually planned
- It remains open whether 13 degrees of freedom suffice for the drills and welding torches the company names as target applications
Sources
- IEEE Spectrum — Atlas Robot's New Hand May Outperform Human-Like Designs
- Humanoids Daily — Boston Dynamics Gives Atlas Four-Finger Hands Built for Tools and AI Training
- Boston Dynamics — Training a Humanoid Robot for Hard Work
