Boston Dynamics Gives Atlas a 13-Degree-of-Freedom Hand and Leaves Off the Pinky

Boston Dynamics has put a new hand on its Atlas humanoid: four fingers, 13 degrees of freedom (independently driven joints), and no pinky. The previous Atlas hand had 7.

The specifications come from the company's announcement, as reported by The Robot Report and Interesting Engineering on October 2. Neither write-up links a datasheet, and the figures a buyer would ask for first are missing.

What 13 degrees of freedom buys

The thumb carries 4 degrees of freedom and each of the other three fingers carries 3, which sums to 13. Moving from 7 to 13 is an 86% increase in articulation per hand, and on a robot with two hands it is 12 more actuated joints to build, cool and keep alive.

The company says the hand uses a single actuator type, direct actuation and a fully encapsulated design with no exposed cables. Interesting Engineering adds that the transmissions are backdrivable, meaning an outside force can move the joint, which lets the robot sense contact through the motors themselves. Dense pressure sensors cover the fingertips and palm.

The tasks on the list are in-hand reorientation, sliding grasps, pinch and tripod grasps, and tools: drills, torque drivers, grinders, nail guns and welding torches. Interesting Engineering reports a demonstration of carrying a loaded mini-fridge of more than 100 pounds. That is a vendor demonstration, not a rated payload.

Why the pinky went

Engineer Dylan Thrush said, in The Robot Report's account of the design, that "the additional dexterity and tasks you'd accomplish isn't worth the extra complexity of three more degrees of freedom, size, and power consumption." Leadership also asked staff to tape their pinky and ring finger together for a day, and the team agreed afterwards that the robot did not need the finger.

The arithmetic is simple. A pinky with 3 degrees of freedom would take the hand from 13 to 16, so dropping it removes about 19% of the actuators, and with them the wiring, the failure points and the heat. The number that matters here is not the finger count but the actuator count per hand, because that is what scales with unit cost and with the mean time between repairs.

Georgia is the test site

The hand is designed for mass manufacturing and for training in simulation. The company says the design has high dynamic fidelity so that reinforcement-learned behaviours transfer from simulator to hardware. Reinforcement learning is also the method behind Ataraxos's win over Stratego's top player, though that system never left a datacentre.

The company said the hand will be integrated into Atlas robots at Hyundai Motor Group's Robotics Metaplant Application Center in Georgia, the training site for putting Atlas into automotive manufacturing. That is a sector with volatile volumes of its own: GM's Equinox EV fell more than 90% in the third quarter. For a factory buyer the question is cost per task, and the announcement gives no cost.

Spec	Stated by Boston Dynamics	Published
Degrees of freedom	13 (thumb 4, three fingers at 3)	Yes
Previous hand	7 degrees of freedom	Yes
Grip force, hand weight	Not stated	No
Price, units deployed	Not stated	No

What is still missing

Neither report gives a grip force, a hand weight, a duty cycle, a price or a count of hands in service. A hand that holds a drill in a demonstration is a different claim from one that survives a shift of 8 hours at a customer line, and the announcement does not separate the two.

What would change this read is a published payload and cycle-life figure from the Georgia site. Neither report says when Atlas units with the new hand will start work there.