Boston Dynamics unveils Atlas hand with four fingers and no pinky

Boston Dynamics unveils Atlas hand with four fingers and no pinky

2 min read•Oct 2, 2026•
Liu Wei
Liu Wei

Boston Dynamics unveiled a four-finger, 13-degree-of-freedom hand for its Atlas humanoid, designed for tool use and mass manufacturing, first reported by Therobotreport. That shifts the hand's focus from grasping a wide variety of objects to manipulating them and using tools, with 13 degrees of freedom versus seven on earlier versions.

Previous Atlas hands had seven degrees of freedom and were designed to grasp a large variety of objects; the new hand shifts the focus to manipulating them. The thumb has four degrees of freedom, while each of the other three fingers has three.

Atlas mechanical engineer Dylan Thrush said the team decided a pinky’s added dexterity and tasks did not justify three more degrees of freedom, size, power consumption and actuator complexity. Before the design was finished, Zachary Jackowski asked team members to tape their pinky and ring finger together for a day and report what they could not do; the team agreed the robot hand did not need a pinky.

The hand can slide its thumb’s fingertip along the length and across the width of the other fingers, make pinch grasps between the thumb and any other finger, and form tripodal grasps. The listed capabilities also range from in-hand reorientation and slip recovery to handling tools while pressing their triggers, including drills, power torque drivers, grinders, nail guns and welding torches.

The joints use direct actuation with a single actuator type; the actuators are fully encapsulated, with no fragile cables crossing joints. The hand is similar in size to a large human hand, and Boston Dynamics said several unique actuation technologies maintained strength similar to the previous hand. Dense pressure tactile sensors cover the fingertips and palm and pick up small contact signals.

Boston Dynamics considers reinforcement learning in simulation essential to dexterous manipulation. Human demonstrations capture visual complexity, the company said, but wearable devices do not capture the high-rate closed-loop control and force regulation involved in fast, agile manipulation. Rigid-drive actuation and a backdrivable transmission, together with controls innovation to compensate for cogging and friction, make it possible to simulate the hand with high dynamic fidelity, the company said. Boston Dynamics said initial results show promising sim-to-real transfer in dynamic tasks; behaviors trained in simulation with domain randomization run on hardware using only high-rate actuator proprioception for feedback.

Arizona appeals court vacates manslaughter sentence after AI video

An Arizona appeals court vacated the 10.5-year sentence of Gabriel Horcasitas while upholding his manslaughter conviction, first reported by Nytimes. The case returns to Maricopa County Superior Court for resentencing without the video, after judges found that it presented scripted statements as if the victim himself were speaking in court.

The three-judge panel said the video generated a likeness of Christopher Pelkey’s voice and appearance but did not reflect actual events. It found that allowing and relying on the video made the sentencing fundamentally unfair, and noted that no prior Arizona case had addressed the admissibility of such a depiction at sentencing.

The judges said a victim’s right to speak cannot override a defendant’s right to be sentenced on accurate, reliable information. They said the video collapsed the distinction between the family’s belief about what Pelkey would have said and Pelkey’s own voice and opinions.

The ruling distinguishes family members speaking about Pelkey from a generated likeness that appeared to speak for him.

Pelkey’s sister, Stacey Wales, presented the video during Horcasitas’s sentencing alongside victim-impact statements from family and friends. Wales wrote the script and said her husband and the couple’s longtime business partner helped create the video using Pelkey’s voice from a YouTube video and his face and torso from a funeral-service poster.

Judge Todd F. Lang praised the video as genuine, then imposed the maximum sentence of 10.5 years, more than the nine years prosecutors had sought.

Wales said nobody intended to make the court believe Pelkey was alive or that he had recorded the video before his death. She said she disagreed with the ruling and argued that families use slide shows, collages, hypothetical conversations and poetry to convey grief.

Wales compared the AI video with photography, saying it took 15 years of landmark cases around the 1860s before photography was widely accepted in courts.

The case returns to Maricopa County Superior Court for a new sentencing hearing without the AI-generated video.